Subject: ibis-users V1 #28
From: owner-ibis-users@ (ibis-users)
To: [email-masked]

ibis-users           Friday, August 15 2003           Volume 01 : Number 028

----------------------------------------------------------------------

Date: Fri, 1 Aug 2003 15:20:09 -0700
From: "Abril, Giovanni" <[email-masked]>
Subject: RE: [IBIS-Users] C_comp value in IBIS model

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Thanks Weston.
=20
Is there a way for me to vary the capacitance in accordance with the =
spec then?  The way you explained it, I should have the same C_comp =
value for typ, min and max, an extracted value, right?  I'll assume ICX =
does it this way, since you work for Mentor.  If the measured value =
turns out to be say 6pF, how would I cover a spec of 2.5pF?

- -----Original Message-----
From: Beal, Weston [mailto:[email-masked]]
Sent: Friday, August 01, 2003 3:16 PM
To: 'Kim Helliwell'; Abril, Giovanni
Cc: [email-masked]
Subject: RE: [IBIS-Users] C_comp value in IBIS model

The effect of C_comp is only double counted if you are using a =
substandard simulator.  All the major simulators that I know of expect =
C_comp to be specified with the same (static approximation) value as =
what is included in the waveforms.  Somewhere in the simulator this is =
reconciled.  Usually it is done is such a way that the capacitive effect =
is calculated out of the waveforms and then the lumped capacitor is =
present at the pin during the transient simulation..
=20
As Arpad noted, the capacitive effect is usually impossible to remove =
from the SPICE models used to derive IBIS data.  It is part of the =
transistor models.  Arpad and others have proposed methods of finding =
the best static value of the die capacitance to use for C_comp and this =
value needs to be there.  If you put the value of 0 for C_comp then the =
simulator will try to back out the capacitance and put no capacitance at =
the pin.  At first this seems OK because the waveforms still have all =
the capacitive effect.  The problem appears when a reflected signal hits =
this pin or if this pin is hi-Z.  There would be no capacitive loading =
and you would then have invalid simulations.
=20
C_comp is your friend.  Embrace it.  ( and enhance it )
=20
Regards,
Weston
=20

- -----Original Message-----
From: Kim Helliwell [mailto:[email-masked]]
Sent: Friday, August 01, 2003 2:45 PM
To: Abril, Giovanni
Cc: [email-masked]
Subject: Re: [IBIS-Users] C_comp value in IBIS model

If the waveforms already include the effects of C_comp, putting=20

the C_comp value in the IBIS model will double-count the effect=20

of C_comp, which is probably not what you want.=20

I feel certain that the right thing to do is re-run the spice sims=20

with C_comp removed from the simulations, and put the correct=20

typ/min/max values of C_comp directly in the IBIS model=20

If I were your customer trying to use this model, I'd be really unhappy=20

to find that C_comp was (silently) being double counted. And I'd=20

be suspicious of your model if C_comp were 0 with no explanation.=20

At the very least, if you don't want to re-run things, you should set=20

C_comp to 0 but put in a comment that the reason it's zero is that=20

the effects of C_comp are included in the rising/falling waveforms.=20

But this is definitely a distant second-best, in my opinion.=20

Kim=20

On Friday, August 1, 2003, at 02:13 PM, Abril, Giovanni wrote:=20

Hello IBIS gurus,=20

I've created an IBIS model using a spice netlist from the vendor, and =
I'm wondering what to do with C_comp.  My rising and falling waveforms =
include the effect of C_comp, but what should I put in the IBIS model?  =
I have a spec sheet that says min C_comp is 2.8pF, max is 10pF.  =
Currently I have 5.0pF for typ, 2.8pF min and 10pF max.=20

Thanks,=20

Giovanni=20

Kim Helliwell=20

Apple Computer=20

[email-masked]=20

408 974 9936=20

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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META HTTP-EQUIV=3D"Content-Type" CONTENT=3D"text/html; =
charset=3Diso-8859-1">
<TITLE></TITLE>

<META content=3D"MSHTML 5.50.4916.2300" name=3DGENERATOR></HEAD>
<BODY>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN =
class=3D851491722-01082003>Thanks=20
Weston.</SPAN></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN=20
class=3D851491722-01082003></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN =
class=3D851491722-01082003>Is=20
there a way for me to vary the capacitance in accordance with the spec=20
then?&nbsp; The way you explained it, I should have the same C_comp =
value for=20
typ, min and max, an extracted value, right?&nbsp; I'll assume ICX does =
it this=20
way, since you work for Mentor.&nbsp; If the measured value turns out to =
be say=20
6pF, how would I cover a spec of 2.5pF?</SPAN></FONT></DIV>
<BLOCKQUOTE dir=3Dltr style=3D"MARGIN-RIGHT: 0px">
  <DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
  size=3D2>-----Original Message-----<BR><B>From:</B> Beal, Weston=20
  [mailto:[email-masked]]<BR><B>Sent:</B> Friday, August 01, =
2003 3:16=20
  PM<BR><B>To:</B> 'Kim Helliwell'; Abril, Giovanni<BR><B>Cc:</B>=20
  [email-masked]<BR><B>Subject:</B> RE: [IBIS-Users] C_comp value in =
IBIS=20
  model<BR><BR></FONT></DIV>
  <DIV><SPAN class=3D495500522-01082003><FONT face=3DArial =
color=3D#0000ff size=3D2>The=20
  effect of C_comp is only double counted if you are using a substandard =

  simulator.&nbsp; All the major simulators that I know of expect C_comp =
to be=20
  specified with the same (static approximation) value as what is =
included in=20
  the waveforms.&nbsp; Somewhere in the simulator this is =
reconciled.&nbsp;=20
  Usually it is done is such a way that the capacitive effect is =
calculated out=20
  of the waveforms and then the lumped capacitor is present at the pin =
during=20
  the transient simulation..</FONT></SPAN></DIV>
  <DIV><SPAN class=3D495500522-01082003><FONT face=3DArial =
color=3D#0000ff=20
  size=3D2></FONT></SPAN>&nbsp;</DIV>
  <DIV><SPAN class=3D495500522-01082003><FONT face=3DArial =
color=3D#0000ff size=3D2>As=20
  Arpad noted, the capacitive effect is usually impossible to remove =
from the=20
  SPICE models used to derive IBIS data.&nbsp; It is part of the =
transistor=20
  models.&nbsp; Arpad and others have proposed methods of finding the =
best=20
  static value of the die capacitance to use for C_comp and this value =
needs to=20
  be there.&nbsp; If you put the value of 0 for C_comp then the =
simulator will=20
  try to back out the capacitance and put no capacitance at the =
pin.&nbsp; At=20
  first this seems OK because the waveforms still have all the =
capacitive=20
  effect.&nbsp; The problem appears when a reflected signal hits this =
pin or if=20
  this pin is hi-Z.&nbsp; There would be no capacitive loading and you =
would=20
  then have invalid simulations.</FONT></SPAN></DIV>
  <DIV><SPAN class=3D495500522-01082003><FONT face=3DArial =
color=3D#0000ff=20
  size=3D2></FONT></SPAN>&nbsp;</DIV>
  <DIV><SPAN class=3D495500522-01082003><FONT face=3DArial =
color=3D#0000ff=20
  size=3D2>C_comp is your friend.&nbsp; Embrace it.&nbsp; ( and enhance =
it=20
  )</FONT></SPAN></DIV>
  <DIV><SPAN class=3D495500522-01082003><FONT face=3DArial =
color=3D#0000ff=20
  size=3D2></FONT></SPAN>&nbsp;</DIV>
  <DIV><SPAN class=3D495500522-01082003><FONT face=3DArial =
color=3D#0000ff=20
  size=3D2>Regards,</FONT></SPAN></DIV>
  <DIV><SPAN class=3D495500522-01082003><FONT face=3DArial =
color=3D#0000ff=20
  size=3D2>Weston</FONT></SPAN></DIV>
  <DIV><SPAN class=3D495500522-01082003></SPAN>&nbsp;</DIV>
  <BLOCKQUOTE>
    <DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
    size=3D2>-----Original Message-----<BR><B>From:</B> Kim Helliwell=20
    [mailto:[email-masked]]<BR><B>Sent:</B> Friday, August 01, 2003 =
2:45=20
    PM<BR><B>To:</B> Abril, Giovanni<BR><B>Cc:</B>=20
    [email-masked]<BR><B>Subject:</B> Re: [IBIS-Users] C_comp value =
in IBIS=20
    model<BR><BR></FONT></DIV>
    <P>If the waveforms already include the effects of C_comp, putting =
</P>
    <P>the C_comp value in the IBIS model will double-count the effect =
</P>
    <P>of C_comp, which is probably not what you want. </P><BR>
    <P>I feel certain that the right thing to do is re-run the spice =
sims </P>
    <P>with C_comp removed from the simulations, and put the correct =
</P>
    <P>typ/min/max values of C_comp directly in the IBIS model </P><BR>
    <P>If I were your customer trying to use this model, I'd be really =
unhappy=20
    </P>
    <P>to find that C_comp was (silently) being double counted. And I'd =
</P>
    <P>be suspicious of your model if C_comp were 0 with no explanation. =

</P><BR>
    <P>At the very least, if you don't want to re-run things, you should =
set=20
</P>
    <P>C_comp to 0 but put in a comment that the reason it's zero is =
that </P>
    <P>the effects of C_comp are included in the rising/falling =
waveforms.=20
    </P><BR>
    <P>But this is definitely a distant second-best, in my opinion. =
</P><BR>
    <P>Kim </P><BR>
    <P>On Friday, August 1, 2003, at 02:13 PM, Abril, Giovanni wrote: =
</P><BR>
    <P><FONT face=3DArial size=3D2>Hello IBIS gurus,</FONT> </P><BR>
    <P><FONT face=3DArial size=3D2>I've created an IBIS model using a =
spice netlist=20
    from the vendor, and I'm wondering what to do with C_comp.&nbsp; My =
rising=20
    and falling waveforms include the effect of C_comp, but what should =
I put in=20
    the IBIS model?&nbsp; I have a spec sheet that says min C_comp is =
2.8pF, max=20
    is 10pF.&nbsp; Currently I have 5.0pF for typ, 2.8pF min and 10pF=20
    max.</FONT> </P><BR>
    <P><FONT face=3DArial size=3D2>Thanks,</FONT> </P><BR>
    <P><FONT face=3DArial size=3D2>Giovanni</FONT> </P><BR><BR>
    <P>Kim Helliwell </P>
    <P>Apple Computer </P>
    <P>[email-masked] </P>
    <P>408 974 9936 </P><BR></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>

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------------------------------

Date: Fri, 1 Aug 2003 15:52:42 -0700
From: Kim Helliwell <[email-masked]>
Subject: Re: [IBIS-Users] C_comp value in IBIS model

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OK, I sit corrected. Sorry to Giovanni for the misinformation...

Kim

On Friday, August 1, 2003, at 03:05  PM, Muranyi, Arpad wrote:

> Kim,
> =A0
> I hate to argue with you, but your response is quite wrong.
> =A0
> It is not possible, or the least very hard to remove the effects
> of die capacitance from a SPICE model.=A0 So the waveforms that
> were generated from a SPICE simulation will always include the
> effects of C_comp.=A0 Also, putting such a waveform and a C_comp
> value into an IBIS model will not double count C_comp.=A0 This
> is actually how IBIS simulators expect to get the data, because
> they are the ones who do the compensation to avoid double counting.
> =A0
> So Giovanni did exactly the right thing.
> =A0
> The only thing he needs to watch out for is that if he does a
> SPICE vs. IBIS correlation, he should have the value for C_comp
> in the IBIS model that was measured on the SPICE model, and not
> the data sheet number, because the two may not be the same value.
> For correlation work.=A0 However, if the IBIS model needs to be
> according to the data book, using the data book values is the right
> thing to do.=A0 (Remember, the SPICE model may not have all the
> layout related extra capacitances in the circuit, which is the
> case most often when someone has a pre layout model).
> =A0
> Arpad Muranyi
> Intel Corporation
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> =A0
> -----Original Message-----
> From: Kim Helliwell [mailto:[email-masked]]
> Sent: Friday, August 01, 2003 2:45 PM
> To: Abril, Giovanni
> Cc: [email-masked]
> Subject: Re: [IBIS-Users] C_comp value in IBIS model
>
> If the waveforms already include the effects of C_comp, putting
> the C_comp value in the IBIS model will double-count the effect
> of C_comp, which is probably not what you want.
>
> I feel certain that the right thing to do is re-run the spice sims
> with C_comp removed from the simulations, and put the correct
> typ/min/max values of C_comp directly in the IBIS model
>
> If I were your customer trying to use this model, I'd be really =
unhappy
> to find that C_comp was (silently) being double counted. And I'd
> be suspicious of your model if C_comp were 0 with no explanation.
>
> At the very least, if you don't want to re-run things, you should set
> C_comp to 0 but put in a comment that the reason it's zero is that
> the effects of C_comp are included in the rising/falling waveforms.
>
> But this is definitely a distant second-best, in my opinion.
>
> Kim
>
> On Friday, August 1, 2003, at 02:13 PM, Abril, Giovanni wrote:
>
> Hello IBIS gurus,
>
> I've created an IBIS model using a spice netlist from the vendor, and=20=

> I'm wondering what to do with C_comp.=A0 My rising and falling =
waveforms=20
> include the effect of C_comp, but what should I put in the IBIS=20
> model?=A0 I have a spec sheet that says min C_comp is 2.8pF, max is=20
> 10pF.=A0 Currently I have 5.0pF for typ, 2.8pF min and 10pF max.
>
> Thanks,
>
> Giovanni
>
>
> Kim Helliwell
> Apple Computer
> [email-masked]
> 408 974 9936
>
>
Kim Helliwell
Apple Computer
[email-masked]
408 974 9936

- --Apple-Mail-8--133216226
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OK, I sit corrected. Sorry to Giovanni for the misinformation...

Kim

On Friday, August 1, 2003, at 03:05  PM, Muranyi, Arpad wrote:

<excerpt><fixed><fontfamily><param>Courier =
New</param><smaller>Kim,</smaller></fontfamily></fixed>

=A0

<fixed><fontfamily><param>Courier New</param><smaller>I hate to argue
with you, but your response is quite =
wrong.</smaller></fontfamily></fixed>

=A0

<fixed><fontfamily><param>Courier New</param><smaller>It is not
possible, or the least very hard to remove the =
effects</smaller></fontfamily></fixed>

<fixed><fontfamily><param>Courier New</param><smaller>of die
capacitance from a SPICE model.=A0 So the waveforms =
that</smaller></fontfamily></fixed>

<fixed><fontfamily><param>Courier New</param><smaller>were generated
from a SPICE simulation will always include =
the</smaller></fontfamily></fixed>

<fixed><fontfamily><param>Courier New</param><smaller>effects of
C_comp.=A0 Also, putting such a waveform and a =
C_comp</smaller></fontfamily></fixed>

<fixed><fontfamily><param>Courier New</param><smaller>value into an
IBIS model will not double count C_comp.=A0 =
This</smaller></fontfamily></fixed>

<fixed><fontfamily><param>Courier New</param><smaller>is actually how
IBIS simulators expect to get the data, =
because</smaller></fontfamily></fixed>

<fixed><fontfamily><param>Courier New</param><smaller>they are the
ones who do the compensation to avoid double =
counting.</smaller></fontfamily></fixed>

=A0

<fixed><fontfamily><param>Courier New</param><smaller>So Giovanni did
exactly the right thing.</smaller></fontfamily></fixed>

=A0

<fixed><fontfamily><param>Courier New</param><smaller>The only thing
he needs to watch out for is that if he does =
a</smaller></fontfamily></fixed>

<fixed><fontfamily><param>Courier New</param><smaller>SPICE vs. IBIS
correlation, he should have the value for =
C_comp</smaller></fontfamily></fixed>

<fixed><fontfamily><param>Courier New</param><smaller>in the IBIS
model that was measured on the SPICE model, and =
not</smaller></fontfamily></fixed>

<fixed><fontfamily><param>Courier New</param><smaller>the data sheet
number, because the two may not be the same =
value.</smaller></fontfamily></fixed>

<fixed><fontfamily><param>Courier New</param><smaller>For correlation
work.=A0 However, if the IBIS model needs to =
be</smaller></fontfamily></fixed>

<fixed><fontfamily><param>Courier New</param><smaller>according to the
data book, using the data book values is the =
right</smaller></fontfamily></fixed>

<fixed><fontfamily><param>Courier New</param><smaller>thing to do.=A0
(Remember, the SPICE model may not have all =
the</smaller></fontfamily></fixed>

<fixed><fontfamily><param>Courier New</param><smaller>layout related
extra capacitances in the circuit, which is =
the</smaller></fontfamily></fixed>

<fixed><fontfamily><param>Courier New</param><smaller>case most often
when someone has a pre layout model).</smaller></fontfamily></fixed>

=A0

<fixed><fontfamily><param>Courier New</param><smaller>Arpad =
Muranyi</smaller></fontfamily></fixed>

<fixed><fontfamily><param>Courier New</param><smaller>Intel =
Corporation</smaller></fontfamily></fixed>

<fixed><fontfamily><param>Courier =
New</param><smaller>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D</smalle=
r></fontfamily></fixed>

=A0

<fontfamily><param>Tahoma</param><smaller>-----Original Message-----

<bold>From:</bold> Kim Helliwell [mailto:[email-masked]]

<bold>Sent:</bold> Friday, August 01, 2003 2:45 PM

<bold>To:</bold> Abril, Giovanni

<bold>Cc:</bold> [email-masked]

<bold>Subject:</bold> Re: [IBIS-Users] C_comp value in IBIS model

</smaller></fontfamily>If the waveforms already include the effects of
C_comp, putting

the C_comp value in the IBIS model will double-count the effect

of C_comp, which is probably not what you want.

I feel certain that the right thing to do is re-run the spice sims

with C_comp removed from the simulations, and put the correct

typ/min/max values of C_comp directly in the IBIS model

If I were your customer trying to use this model, I'd be really unhappy

to find that C_comp was (silently) being double counted. And I'd

be suspicious of your model if C_comp were 0 with no explanation.

At the very least, if you don't want to re-run things, you should set

C_comp to 0 but put in a comment that the reason it's zero is that

the effects of C_comp are included in the rising/falling waveforms.

But this is definitely a distant second-best, in my opinion.

Kim

On Friday, August 1, 2003, at 02:13 PM, Abril, Giovanni wrote:

<fontfamily><param>Arial</param><smaller>Hello IBIS =
gurus,</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>I've created an IBIS model
using a spice netlist from the vendor, and I'm wondering what to do
with C_comp.=A0 My rising and falling waveforms include the effect of
C_comp, but what should I put in the IBIS model?=A0 I have a spec sheet
that says min C_comp is 2.8pF, max is 10pF.=A0 Currently I have 5.0pF
for typ, 2.8pF min and 10pF max.</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>Thanks,</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>Giovanni</smaller></fontfamily>

Kim Helliwell

Apple Computer

[email-masked]

408 974 9936

</excerpt>Kim Helliwell

Apple Computer

[email-masked]

408 974 9936

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------------------------------

Date: Fri, 1 Aug 2003 16:05:45 -0700 
From: "Beal, Weston" <[email-masked]>
Subject: RE: [IBIS-Users] C_comp value in IBIS model

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Giovanni,
 
The best solution would be to use your favorite C_comp calculation algorithm to calculate the typical value.  Then use the datasheet values for min and max.  When I'm in a hurry or have a non-critical model I usually set the typical value to something a little bit below the average of the min and max values from the data sheet.
 
There have been a couple of presentations at IBIS summits about how to find values for C_comp.  You can check the archives for those presentations.
 
Regards,
Weston

- -----Original Message-----
From: Abril, Giovanni [mailto:[email-masked]]
Sent: Friday, August 01, 2003 3:20 PM
To: Beal, Weston; [email-masked]
Cc: [email-masked]
Subject: RE: [IBIS-Users] C_comp value in IBIS model

Thanks Weston.
 
Is there a way for me to vary the capacitance in accordance with the spec then?  The way you explained it, I should have the same C_comp value for typ, min and max, an extracted value, right?  I'll assume ICX does it this way, since you work for Mentor.  If the measured value turns out to be say 6pF, how would I cover a spec of 2.5pF?

- -----Original Message-----
From: Beal, Weston [mailto:[email-masked]]
Sent: Friday, August 01, 2003 3:16 PM
To: 'Kim Helliwell'; Abril, Giovanni
Cc: [email-masked]
Subject: RE: [IBIS-Users] C_comp value in IBIS model

The effect of C_comp is only double counted if you are using a substandard simulator.  All the major simulators that I know of expect C_comp to be specified with the same (static approximation) value as what is included in the waveforms.  Somewhere in the simulator this is reconciled.  Usually it is done is such a way that the capacitive effect is calculated out of the waveforms and then the lumped capacitor is present at the pin during the transient simulation..
 
As Arpad noted, the capacitive effect is usually impossible to remove from the SPICE models used to derive IBIS data.  It is part of the transistor models.  Arpad and others have proposed methods of finding the best static value of the die capacitance to use for C_comp and this value needs to be there.  If you put the value of 0 for C_comp then the simulator will try to back out the capacitance and put no capacitance at the pin.  At first this seems OK because the waveforms still have all the capacitive effect.  The problem appears when a reflected signal hits this pin or if this pin is hi-Z.  There would be no capacitive loading and you would then have invalid simulations.
 
C_comp is your friend.  Embrace it.  ( and enhance it )
 
Regards,
Weston

- -----Original Message-----
From: Kim Helliwell [mailto:[email-masked]]
Sent: Friday, August 01, 2003 2:45 PM
To: Abril, Giovanni
Cc: [email-masked]
Subject: Re: [IBIS-Users] C_comp value in IBIS model

If the waveforms already include the effects of C_comp, putting 

the C_comp value in the IBIS model will double-count the effect 

of C_comp, which is probably not what you want. 

I feel certain that the right thing to do is re-run the spice sims 

with C_comp removed from the simulations, and put the correct 

typ/min/max values of C_comp directly in the IBIS model 

If I were your customer trying to use this model, I'd be really unhappy 

to find that C_comp was (silently) being double counted. And I'd 

be suspicious of your model if C_comp were 0 with no explanation. 

At the very least, if you don't want to re-run things, you should set 

C_comp to 0 but put in a comment that the reason it's zero is that 

the effects of C_comp are included in the rising/falling waveforms. 

But this is definitely a distant second-best, in my opinion. 

Kim 

On Friday, August 1, 2003, at 02:13 PM, Abril, Giovanni wrote: 

Hello IBIS gurus, 

I've created an IBIS model using a spice netlist from the vendor, and I'm wondering what to do with C_comp.  My rising and falling waveforms include the effect of C_comp, but what should I put in the IBIS model?  I have a spec sheet that says min C_comp is 2.8pF, max is 10pF.  Currently I have 5.0pF for typ, 2.8pF min and 10pF max. 

Thanks, 

Giovanni 

Kim Helliwell 

Apple Computer 

[email-masked] 

408 974 9936 

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<DIV><SPAN class=092030023-01082003><FONT face=Arial color=#0000ff 
size=2>Giovanni,</FONT></SPAN></DIV>
<DIV><SPAN class=092030023-01082003><FONT face=Arial color=#0000ff 
size=2></FONT></SPAN>&nbsp;</DIV>
<DIV><SPAN class=092030023-01082003><FONT face=Arial color=#0000ff size=2>The 
best solution would be to use your favorite C_comp calculation algorithm to 
calculate the typical value.&nbsp; Then use the datasheet values for min and 
max.&nbsp; When I'm in a hurry or have a non-critical model I usually set the 
typical value to something a little bit below the average of the min and max 
values from the data sheet.</FONT></SPAN></DIV>
<DIV><SPAN class=092030023-01082003><FONT face=Arial color=#0000ff 
size=2></FONT></SPAN>&nbsp;</DIV>
<DIV><SPAN class=092030023-01082003><FONT face=Arial color=#0000ff size=2>There 
have been a couple of presentations at IBIS summits about how to find values for 
C_comp.&nbsp; You can check the archives for those 
presentations.</FONT></SPAN></DIV>
<DIV><SPAN class=092030023-01082003></SPAN>&nbsp;</DIV>
<DIV><SPAN class=092030023-01082003><FONT face=Arial color=#0000ff 
size=2>Regards,</FONT></SPAN></DIV>
<DIV><SPAN class=092030023-01082003><FONT face=Arial color=#0000ff 
size=2>Weston</FONT></SPAN></DIV>
<DIV><SPAN class=092030023-01082003><FONT face=Arial color=#0000ff 
size=2></FONT></SPAN>&nbsp;</DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
  <DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma 
  size=2>-----Original Message-----<BR><B>From:</B> Abril, Giovanni 
  [mailto:[email-masked]]<BR><B>Sent:</B> Friday, August 01, 2003 3:20 
  PM<BR><B>To:</B> Beal, Weston; [email-masked]<BR><B>Cc:</B> 
  [email-masked]<BR><B>Subject:</B> RE: [IBIS-Users] C_comp value in IBIS 
  model<BR><BR></FONT></DIV>
  <DIV><FONT face=Arial color=#0000ff size=2><SPAN 
  class=851491722-01082003>Thanks Weston.</SPAN></FONT></DIV>
  <DIV><FONT face=Arial color=#0000ff size=2><SPAN 
  class=851491722-01082003></SPAN></FONT>&nbsp;</DIV>
  <DIV><FONT face=Arial color=#0000ff size=2><SPAN class=851491722-01082003>Is 
  there a way for me to vary the capacitance in accordance with the spec 
  then?&nbsp; The way you explained it, I should have the same C_comp value for 
  typ, min and max, an extracted value, right?&nbsp; I'll assume ICX does it 
  this way, since you work for Mentor.&nbsp; If the measured value turns out to 
  be say 6pF, how would I cover a spec of 2.5pF?</SPAN></FONT></DIV>
  <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
    <DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma 
    size=2>-----Original Message-----<BR><B>From:</B> Beal, Weston 
    [mailto:[email-masked]]<BR><B>Sent:</B> Friday, August 01, 2003 
    3:16 PM<BR><B>To:</B> 'Kim Helliwell'; Abril, Giovanni<BR><B>Cc:</B> 
    [email-masked]<BR><B>Subject:</B> RE: [IBIS-Users] C_comp value in IBIS 
    model<BR><BR></FONT></DIV>
    <DIV><SPAN class=495500522-01082003><FONT face=Arial color=#0000ff 
    size=2>The effect of C_comp is only double counted if you are using a 
    substandard simulator.&nbsp; All the major simulators that I know of expect 
    C_comp to be specified with the same (static approximation) value as what is 
    included in the waveforms.&nbsp; Somewhere in the simulator this is 
    reconciled.&nbsp; Usually it is done is such a way that the capacitive 
    effect is calculated out of the waveforms and then the lumped capacitor is 
    present at the pin during the transient simulation..</FONT></SPAN></DIV>
    <DIV><SPAN class=495500522-01082003><FONT face=Arial color=#0000ff 
    size=2></FONT></SPAN>&nbsp;</DIV>
    <DIV><SPAN class=495500522-01082003><FONT face=Arial color=#0000ff size=2>As 
    Arpad noted, the capacitive effect is usually impossible to remove from the 
    SPICE models used to derive IBIS data.&nbsp; It is part of the transistor 
    models.&nbsp; Arpad and others have proposed methods of finding the best 
    static value of the die capacitance to use for C_comp and this value needs 
    to be there.&nbsp; If you put the value of 0 for C_comp then the simulator 
    will try to back out the capacitance and put no capacitance at the 
    pin.&nbsp; At first this seems OK because the waveforms still have all the 
    capacitive effect.&nbsp; The problem appears when a reflected signal hits 
    this pin or if this pin is hi-Z.&nbsp; There would be no capacitive loading 
    and you would then have invalid simulations.</FONT></SPAN></DIV>
    <DIV><SPAN class=495500522-01082003><FONT face=Arial color=#0000ff 
    size=2></FONT></SPAN>&nbsp;</DIV>
    <DIV><SPAN class=495500522-01082003><FONT face=Arial color=#0000ff 
    size=2>C_comp is your friend.&nbsp; Embrace it.&nbsp; ( and enhance it 
    )</FONT></SPAN></DIV>
    <DIV><SPAN class=495500522-01082003><FONT face=Arial color=#0000ff 
    size=2></FONT></SPAN>&nbsp;</DIV>
    <DIV><SPAN class=495500522-01082003><FONT face=Arial color=#0000ff 
    size=2>Regards,</FONT></SPAN></DIV>
    <DIV><SPAN class=495500522-01082003><FONT face=Arial color=#0000ff 
    size=2>Weston</FONT></SPAN></DIV>
    <DIV><SPAN class=495500522-01082003></SPAN>&nbsp;</DIV>
    <BLOCKQUOTE>
      <DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma 
      size=2>-----Original Message-----<BR><B>From:</B> Kim Helliwell 
      [mailto:[email-masked]]<BR><B>Sent:</B> Friday, August 01, 2003 2:45 
      PM<BR><B>To:</B> Abril, Giovanni<BR><B>Cc:</B> 
      [email-masked]<BR><B>Subject:</B> Re: [IBIS-Users] C_comp value in 
      IBIS model<BR><BR></FONT></DIV>
      <P>If the waveforms already include the effects of C_comp, putting </P>
      <P>the C_comp value in the IBIS model will double-count the effect </P>
      <P>of C_comp, which is probably not what you want. </P><BR>
      <P>I feel certain that the right thing to do is re-run the spice sims </P>
      <P>with C_comp removed from the simulations, and put the correct </P>
      <P>typ/min/max values of C_comp directly in the IBIS model </P><BR>
      <P>If I were your customer trying to use this model, I'd be really unhappy 
      </P>
      <P>to find that C_comp was (silently) being double counted. And I'd </P>
      <P>be suspicious of your model if C_comp were 0 with no explanation. 
      </P><BR>
      <P>At the very least, if you don't want to re-run things, you should set 
      </P>
      <P>C_comp to 0 but put in a comment that the reason it's zero is that </P>
      <P>the effects of C_comp are included in the rising/falling waveforms. 
      </P><BR>
      <P>But this is definitely a distant second-best, in my opinion. </P><BR>
      <P>Kim </P><BR>
      <P>On Friday, August 1, 2003, at 02:13 PM, Abril, Giovanni wrote: </P><BR>
      <P><FONT face=Arial size=2>Hello IBIS gurus,</FONT> </P><BR>
      <P><FONT face=Arial size=2>I've created an IBIS model using a spice 
      netlist from the vendor, and I'm wondering what to do with C_comp.&nbsp; 
      My rising and falling waveforms include the effect of C_comp, but what 
      should I put in the IBIS model?&nbsp; I have a spec sheet that says min 
      C_comp is 2.8pF, max is 10pF.&nbsp; Currently I have 5.0pF for typ, 2.8pF 
      min and 10pF max.</FONT> </P><BR>
      <P><FONT face=Arial size=2>Thanks,</FONT> </P><BR>
      <P><FONT face=Arial size=2>Giovanni</FONT> </P><BR><BR>
      <P>Kim Helliwell </P>
      <P>Apple Computer </P>
      <P>[email-masked] </P>
      <P>408 974 9936 </P><BR></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>

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Date: Wed, 6 Aug 2003 11:25:12 +0200
From: [email-masked]
Subject: [IBIS-Users] How to determine Ccomp

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Dear IBIS collegues,

What is the best way to determine Ccomp?
Basically there are two ways: applying a ramp to the output terminal and 
calculate Ccomp from the slew-rate, or connecting an inductor to the 
output and calculate the Ccomp from the resonace frequency.
Which method gives the best results? > always, or application dependent?
How is this done for differential outputs. Outputs like LVDS have internal 
feedback loops to control the common level. Must something be done with 
the "other" output? Is the peaking a reliable measure for the value of 
Ccomp, or may the added inductor shift the poles and zeros of the feedback 
buffer due this load causing a peaking that is not just the parallel 
connection of Ccomp and the test inductor?

With kind regards,

Ir. Erik van der Ven
Room DB1032
Business Line Networking Infrastructure
Philips Semiconductors BV
Gerstweg 2
6534 AE Nijmegen
The Netherlands
Phone: +31-24-3534334
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<br><font size=2 face="sans-serif">Dear IBIS collegues,</font>
<br>
<br><font size=2 face="sans-serif">What is the best way to determine Ccomp?</font>
<br><font size=2 face="sans-serif">Basically there are two ways: applying a ramp to the output terminal and calculate Ccomp from the slew-rate, or connecting an inductor to the output and calculate the Ccomp from the resonace frequency.</font>
<br><font size=2 face="sans-serif">Which method gives the best results? &gt; always, or application dependent?</font>
<br><font size=2 face="sans-serif">How is this done for differential outputs. Outputs like LVDS have internal feedback loops to control the common level. Must something be done with the &quot;other&quot; output? Is the peaking a reliable measure for the value of Ccomp, or may the added inductor shift the poles and zeros of the feedback buffer due this load causing a peaking that is not just the parallel connection of Ccomp and the test inductor?</font>
<br>
<br><font size=2 face="sans-serif">With kind regards,</font>
<br>
<br><font size=2 face="sans-serif"><br>
Ir. Erik van der Ven<br>
Room DB1032<br>
Business Line Networking Infrastructure<br>
Philips Semiconductors BV<br>
Gerstweg 2<br>
6534 AE Nijmegen<br>
The Netherlands<br>
Phone: +31-24-3534334</font>
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------------------------------

Date: Wed, 6 Aug 2003 12:50:04 -0700
From: "Muranyi, Arpad" <[email-masked]>
Subject: RE: [IBIS-Users] C-Comp

Sorry for the late response.

The way this could be done is to simply repeat all C_comp
parameters twice, one set for drive mode, and another for
receive mode.  One C_comp for receive mode would not
be enough.

However, there is more to this problem.  The capacitance
is not only dependent on whether the buffer drives or
receives, but it is also voltage and frequency dependent.
(See BIRD 79 and related presentations).  The question
in my mind is, BIRD 79 was voted down, because all those
features will be doable with the *-AMS extensions to IBIS.
The same is true for the C_comp drive/receive parameters.

Is it worth adding these parameters to the existing
style, or should we just go with the *-AMS style modeling
and be able to describe anything freely?

Arpad
============================================================

- -----Original Message-----
From: Kim Helliwell [mailto:[email-masked]]
Sent: Friday, July 18, 2003 1:31 PM
To: Robert Haller
Cc: Roy Leventhal; [email-masked]; [email-masked]
Subject: Re: [IBIS-Users] C-Comp

I'm just curious how this would be folded in with the 4-part C_comp
(BIRD 76.1). Will we end up with 2 (or even 4) more C_comp
values? Or does just 1 value adequately characterize the
receiver?

Kim

On Friday, July 18, 2003, at 10:10  AM, Robert Haller wrote:

> IBIS users,
>
> At today's IBIS open forum call, the issue was raised concerning the 
> limitations of Ccomp in the present IBIS spec. This issue is being 
> added to the next ibis open forum agenda technical discussion.
>
> I would like to solicit feedback from Model developers and users for 
> proposed changes, as well as voice my own opinion.
>
> Present syntax
>
> |      typ     min     max
> |
> C_comp 3.90pF  3.10pF  4.80pF
>
> My personal experience has shown that I/O buffer often have different 
> C_comp when driving and receiving. To keep things simple, I would 
> suggest that a simple extension to the C_comp would be to specify a 
> C_comp driving and C_comp receiving for  Model_type = I/O
>
> regards,
> bob
> -- 
> Robert J. Haller ([email-masked])
> Principal Consultant
> Signal Integrity Software Inc.
> 6 Clock Tower Place, Suite 250
> Maynard, MA 01754
> Phone: (978) 461-0449, ext 15
>
>
>
> Roy Leventhal wrote:
>> Anshuli,
>> Be aware that capacitive behavior is included in the V-T behavioral 
>> curves
>> and/or the slew rates based on them. Unsophisticated providers of 
>> simulation
>> software (hopefully, few remain) can thus mistakenly "double count" 
>> the
>> effects of Ccomp unless they adjust for its presence in the circuit.
>> So, why is Ccomp included? To account for the capacitive loading on 
>> the
>> circuit, direct or reflected wave, and it is the total capacitive 
>> loading
>> looking into the die pad.
>> Best Regards,
>> Roy
>
>
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------------------------------

Date: Wed, 6 Aug 2003 13:23:35 -0700
From: "Muranyi, Arpad" <[email-masked]>
Subject: RE: [IBIS-Users] How to determine C_comp

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I know of about six methods to measure C_comp:
=20
 =20
*RC time constant with a step function=20
*does not show voltage or frequency dependencies=20
*Time Domain forced saw tooth voltage=20
*can provide voltage dependent capacitance curves=20
*does not show frequency dependence=20
*TDR technique (Time Domain)=20
*does not show voltage or frequency dependencies=20
*Frequency Domain sweep with tank circuit=20
*can provide voltage dependent capacitance curves=20
*does not show frequency dependence(?)=20
*Frequency Domain imaginary current=20
*can provide voltage and frequency dependent capacitance curves=20
*shows frequency dependence very well=20
*Frequency Domain pole/zero method=20
*See BIRD 79 on IBIS web page for details=20
=20
Arpad Muranyi
Intel Corporation
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=20
=20
- -----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Wednesday, August 06, 2003 2:25 AM
To: [email-masked]
Cc: [email-masked]
Subject: [IBIS-Users] How to determine Ccomp

Dear IBIS collegues,=20

What is the best way to determine Ccomp?=20
Basically there are two ways: applying a ramp to the output terminal and =
calculate Ccomp from the slew-rate, or connecting an inductor to the =
output and calculate the Ccomp from the resonace frequency.=20
Which method gives the best results? > always, or application dependent? =

How is this done for differential outputs. Outputs like LVDS have =
internal feedback loops to control the common level. Must something be =
done with the "other" output? Is the peaking a reliable measure for the =
value of Ccomp, or may the added inductor shift the poles and zeros of =
the feedback buffer due this load causing a peaking that is not just the =
parallel connection of Ccomp and the test inductor?=20

With kind regards,=20

Ir. Erik van der Ven
Room DB1032
Business Line Networking Infrastructure
Philips Semiconductors BV
Gerstweg 2
6534 AE Nijmegen
The Netherlands
Phone: +31-24-3534334

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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META HTTP-EQUIV=3D"Content-Type" CONTENT=3D"text/html; =
charset=3Diso-8859-1">

<META content=3D"MSHTML 6.00.2716.2200" name=3DGENERATOR></HEAD>
<BODY>
<DIV><FONT face=3D"Courier New" size=3D2><SPAN =
class=3D781072320-06082003>I know of=20
about six methods to measure C_comp:</SPAN></FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2><SPAN=20
class=3D781072320-06082003></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=3D"Courier New" size=3D2><SPAN =
class=3D781072320-06082003><FONT=20
face=3D"Times New Roman" size=3D3>&nbsp;</FONT>
<DIV style=3D"tab-interval: .9965in" v:shape=3D"_x0000_s3074">
<DIV class=3DO style=3D"mso-margin-left-alt: 143"><SPAN=20
style=3D"LEFT: -3.06%; POSITION: absolute; mso-special-format: =
bullet">&#8226;</SPAN><B>RC=20
time constant with a step function </B></DIV>
<DIV class=3DO1 style=3D"mso-margin-left-alt: 506; mso-text-indent-alt: =
358"><SPAN=20
style=3D"FONT-SIZE: 75%"><SPAN=20
style=3D"LEFT: -3.31%; POSITION: absolute; TOP: 0.3em; =
mso-special-format: bullet">&#8226;</SPAN></SPAN><SPAN=20
style=3D"FONT-SIZE: 75%">does not show voltage or frequency=20
dependencies</SPAN><B><FONT size=3D3> </FONT></B></DIV>
<DIV class=3DO style=3D"mso-margin-left-alt: 143"><SPAN=20
style=3D"LEFT: -3.06%; POSITION: absolute; mso-special-format: =
bullet">&#8226;</SPAN><B>Time=20
Domain forced saw tooth voltage </B></DIV>
<DIV class=3DO1 style=3D"mso-margin-left-alt: 506; mso-text-indent-alt: =
358"><SPAN=20
style=3D"FONT-SIZE: 75%"><SPAN=20
style=3D"LEFT: -3.31%; POSITION: absolute; mso-special-format: =
bullet">&#8226;</SPAN></SPAN><SPAN=20
style=3D"FONT-SIZE: 75%">can provide voltage dependent capacitance =
curves=20
</SPAN></DIV>
<DIV class=3DO1 style=3D"mso-margin-left-alt: 506; mso-text-indent-alt: =
358"><SPAN=20
style=3D"FONT-SIZE: 75%"><SPAN=20
style=3D"LEFT: -3.31%; POSITION: absolute; TOP: 0.3em; =
mso-special-format: bullet">&#8226;</SPAN></SPAN><SPAN=20
style=3D"FONT-SIZE: 75%">does not show frequency =
dependence</SPAN><B><FONT size=3D3>=20
</FONT></B></DIV>
<DIV class=3DO style=3D"mso-margin-left-alt: 143"><SPAN=20
style=3D"LEFT: -3.06%; POSITION: absolute; mso-special-format: =
bullet">&#8226;</SPAN><B>TDR=20
technique (Time Domain) </B></DIV>
<DIV class=3DO1 style=3D"mso-margin-left-alt: 506; mso-text-indent-alt: =
358"><SPAN=20
style=3D"FONT-SIZE: 75%"><SPAN=20
style=3D"LEFT: -3.31%; POSITION: absolute; TOP: 0.3em; =
mso-special-format: bullet">&#8226;</SPAN></SPAN><SPAN=20
style=3D"FONT-SIZE: 75%">does not show voltage or frequency=20
dependencies</SPAN><B><FONT size=3D3> </FONT></B></DIV>
<DIV class=3DO style=3D"mso-margin-left-alt: 143"><SPAN=20
style=3D"LEFT: -3.06%; POSITION: absolute; mso-special-format: =
bullet">&#8226;</SPAN><B>Frequency=20
Domain sweep with tank circuit </B></DIV>
<DIV class=3DO1 style=3D"mso-margin-left-alt: 506; mso-text-indent-alt: =
358"><SPAN=20
style=3D"FONT-SIZE: 75%"><SPAN=20
style=3D"LEFT: -3.31%; POSITION: absolute; mso-special-format: =
bullet">&#8226;</SPAN></SPAN><SPAN=20
style=3D"FONT-SIZE: 75%">can provide voltage dependent capacitance =
curves=20
</SPAN></DIV>
<DIV class=3DO1 style=3D"mso-margin-left-alt: 506; mso-text-indent-alt: =
358"><SPAN=20
style=3D"FONT-SIZE: 75%"><SPAN=20
style=3D"LEFT: -3.31%; POSITION: absolute; TOP: 0.3em; =
mso-special-format: bullet">&#8226;</SPAN></SPAN><SPAN=20
style=3D"FONT-SIZE: 75%">does not show frequency =
dependence(?)</SPAN><B><FONT=20
size=3D3> </FONT></B></DIV>
<DIV class=3DO style=3D"mso-margin-left-alt: 143"><SPAN=20
style=3D"LEFT: -3.06%; POSITION: absolute; mso-special-format: =
bullet">&#8226;</SPAN><B>Frequency=20
Domain imaginary current </B></DIV>
<DIV class=3DO1 style=3D"mso-margin-left-alt: 506; mso-text-indent-alt: =
358"><SPAN=20
style=3D"FONT-SIZE: 75%"><SPAN=20
style=3D"LEFT: -3.23%; POSITION: absolute; mso-special-format: =
bullet">&#8226;</SPAN></SPAN><SPAN=20
style=3D"FONT-SIZE: 75%">can provide voltage and frequency dependent =
capacitance=20
curves </SPAN></DIV>
<DIV class=3DO1 style=3D"mso-margin-left-alt: 506; mso-text-indent-alt: =
358"><SPAN=20
style=3D"FONT-SIZE: 75%"><SPAN=20
style=3D"LEFT: -3.31%; POSITION: absolute; TOP: 0.3em; =
mso-special-format: bullet">&#8226;</SPAN></SPAN><SPAN=20
style=3D"FONT-SIZE: 75%">shows frequency dependence very =
well</SPAN><B><FONT=20
size=3D3> </FONT></B></DIV>
<DIV class=3DO style=3D"mso-margin-left-alt: 143"><SPAN=20
style=3D"LEFT: -3.06%; POSITION: absolute; mso-special-format: =
bullet">&#8226;</SPAN><B>Frequency=20
Domain pole/zero method </B></DIV>
<DIV class=3DO1 style=3D"mso-margin-left-alt: 506; mso-text-indent-alt: =
358"><SPAN=20
style=3D"FONT-SIZE: 75%"><SPAN=20
style=3D"LEFT: -3.31%; POSITION: absolute; mso-special-format: =
bullet">&#8226;</SPAN></SPAN><SPAN=20
style=3D"FONT-SIZE: 75%">See BIRD 79 on IBIS web page for details =
</SPAN></DIV>
<DIV class=3DO=20
style=3D"mso-margin-left-alt: 143; mso-line-spacing: '100 50 0'"><SPAN=20
style=3D"DISPLAY: none; mso-special-format: =
lastCR"></SPAN></DIV></DIV></SPAN></FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2><SPAN=20
class=3D781072320-06082003></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=3D"Courier New" size=3D2><SPAN =
class=3D781072320-06082003>Arpad=20
Muranyi</SPAN></FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2><SPAN =
class=3D781072320-06082003>Intel=20
Corporation</SPAN></FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2><SPAN=20
class=3D781072320-06082003>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D</SPAN></FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2><SPAN=20
class=3D781072320-06082003></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=3D"Courier New" size=3D2><SPAN=20
class=3D781072320-06082003></SPAN></FONT>&nbsp;</DIV>
<DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
size=3D2>-----Original Message-----<BR><B>From:</B> =
[email-masked]=20
[mailto:[email-masked]]<BR><B>Sent:</B> Wednesday, August =
06, 2003=20
2:25 AM<BR><B>To:</B> [email-masked]<BR><B>Cc:</B>=20
[email-masked]<BR><B>Subject:</B> [IBIS-Users] How to =
determine=20
Ccomp<BR><BR></FONT></DIV><BR><FONT face=3Dsans-serif size=3D2>Dear IBIS =

collegues,</FONT> <BR><BR><FONT face=3Dsans-serif size=3D2>What is the =
best way to=20
determine Ccomp?</FONT> <BR><FONT face=3Dsans-serif size=3D2>Basically =
there are two=20
ways: applying a ramp to the output terminal and calculate Ccomp from =
the=20
slew-rate, or connecting an inductor to the output and calculate the =
Ccomp from=20
the resonace frequency.</FONT> <BR><FONT face=3Dsans-serif =
size=3D2>Which method=20
gives the best results? &gt; always, or application dependent?</FONT> =
<BR><FONT=20
face=3Dsans-serif size=3D2>How is this done for differential outputs. =
Outputs like=20
LVDS have internal feedback loops to control the common level. Must =
something be=20
done with the "other" output? Is the peaking a reliable measure for the =
value of=20
Ccomp, or may the added inductor shift the poles and zeros of the =
feedback=20
buffer due this load causing a peaking that is not just the parallel =
connection=20
of Ccomp and the test inductor?</FONT> <BR><BR><FONT face=3Dsans-serif =
size=3D2>With=20
kind regards,</FONT> <BR><BR><FONT face=3Dsans-serif size=3D2><BR>Ir. =
Erik van der=20
Ven<BR>Room DB1032<BR>Business Line Networking Infrastructure<BR>Philips =

Semiconductors BV<BR>Gerstweg 2<BR>6534 AE Nijmegen<BR>The =
Netherlands<BR>Phone:=20
+31-24-3534334</FONT></BODY></HTML>

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------------------------------

Date: Thu, 7 Aug 2003 09:29:12 +0200
From: [email-masked]
Subject: Re: [IBIS-Users] How to determine Ccomp

This is a multipart message in MIME format.
- --=_alternative 00295778C1256D7B_=
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Hello Dekker,

Thank you for your response. I meant determination of Ccomp by 
simulations, sorry.

Best regards,
Erik.

Ir. Erik van der Ven
Room DB1032
Business Line Networking Infrastructure
Philips Semiconductors BV
Gerstweg 2
6534 AE Nijmegen
The Netherlands
Phone: +31-24-3534334

"Dekker Graden" <[email-masked]>
08/06/03 06:11 PM
Please respond to "Dekker Graden"

        To:     Erik van der Ven/NYM/SC/PHILIPS@EMEA2
        cc: 
        Subject:        Re: [IBIS-Users] How to determine Ccomp
        Classification: 

Hello Erik
 
If your talking about getting Ccomp from measurements there is another way 
of doing it that I have found to be quite good using a TDR. The 
measurement method depends on if you have packaged or die only chips. 
Anyway.... you just use a TDR to shoot in a pulse... then use something 
like Iconnect (TDA systems software) to calculate what Ccomp is from the 
waveform you get. 
 
There are papers and application notes on http://www.tdasystems.com site that explain this way of getting Ccomp. 
 
The only down side here is that you tend to only get the basic Ccomp... 
about typical.
 
Anyway... just a pointer to a different direction if its an option for 
you. The software and equipment is rather spendy.
 
Dekker
- ----- Original Message ----- 
From: [email-masked] 
To: [email-masked] 
Cc: [email-masked] 
Sent: Wednesday, August 06, 2003 2:25 AM
Subject: [IBIS-Users] How to determine Ccomp

Dear IBIS collegues, 

What is the best way to determine Ccomp? 
Basically there are two ways: applying a ramp to the output terminal and 
calculate Ccomp from the slew-rate, or connecting an inductor to the 
output and calculate the Ccomp from the resonace frequency. 
Which method gives the best results? > always, or application dependent? 
How is this done for differential outputs. Outputs like LVDS have internal 
feedback loops to control the common level. Must something be done with 
the "other" output? Is the peaking a reliable measure for the value of 
Ccomp, or may the added inductor shift the poles and zeros of the feedback 
buffer due this load causing a peaking that is not just the parallel 
connection of Ccomp and the test inductor? 

With kind regards, 

Ir. Erik van der Ven
Room DB1032
Business Line Networking Infrastructure
Philips Semiconductors BV
Gerstweg 2
6534 AE Nijmegen
The Netherlands
Phone: +31-24-3534334

- --=_alternative 00295778C1256D7B_=
Content-Type: text/html; charset="us-ascii"

<br><font size=2 face="sans-serif">Hello Dekker,</font>
<br>
<br>
<br><font size=2 face="sans-serif">Thank you for your response. I meant determination of Ccomp by simulations, sorry.</font>
<br>
<br><font size=2 face="sans-serif">Best regards,</font>
<br><font size=2 face="sans-serif">Erik.</font>
<br><font size=2 face="sans-serif"><br>
Ir. Erik van der Ven<br>
Room DB1032<br>
Business Line Networking Infrastructure<br>
Philips Semiconductors BV<br>
Gerstweg 2<br>
6534 AE Nijmegen<br>
The Netherlands<br>
Phone: +31-24-3534334</font>
<br>
<br>
<br>
<table width=100%>
<tr valign=top>
<td>
<td>
<br>
<br>
<br>
<br>
<br><font size=1 face="sans-serif"><b>&quot;Dekker Graden&quot; &lt;[email-masked]&gt;</b></font>
<p><font size=1 face="sans-serif">08/06/03 06:11 PM</font>
<br><font size=1 face="sans-serif">Please respond to &quot;Dekker Graden&quot;</font>
<br>
<td><font size=1 face="Arial">&nbsp; &nbsp; &nbsp; &nbsp; </font>
<br><font size=1 face="sans-serif">&nbsp; &nbsp; &nbsp; &nbsp; To: &nbsp; &nbsp; &nbsp; &nbsp;Erik van der Ven/NYM/SC/PHILIPS@EMEA2</font>
<br><font size=1 face="sans-serif">&nbsp; &nbsp; &nbsp; &nbsp; cc: &nbsp; &nbsp; &nbsp; &nbsp;</font>
<br><font size=1 face="sans-serif">&nbsp; &nbsp; &nbsp; &nbsp; Subject: &nbsp; &nbsp; &nbsp; &nbsp;Re: [IBIS-Users] How to determine Ccomp</font>
<p><font size=1 face="sans-serif">&nbsp; &nbsp; &nbsp; &nbsp; Classification: &nbsp; &nbsp; &nbsp; &nbsp;</font>
<br></table>
<br>
<br>
<br><font size=2 face="Arial">Hello Erik</font>
<br><font size=3 face="Times New Roman">&nbsp;</font>
<br><font size=2 face="Arial">If your talking about getting Ccomp from measurements there is another way of doing it that I have found to be quite good using a TDR. The measurement method depends on if you have packaged or die only chips. Anyway.... you just use a TDR to shoot in a pulse... then use something like Iconnect (TDA systems software) to calculate what Ccomp is from the waveform you get. </font>
<br><font size=3 face="Times New Roman">&nbsp;</font>
<br><font size=2 face="Arial">There are papers and application notes on </font><a href=http://www.tdasystems.com/><font size=2 color=blue face="Arial"><u>http://www.tdasystems.com</u></font></a><font size=2 face="Arial"> site that explain this way of getting Ccomp. </font>
<br><font size=3 face="Times New Roman">&nbsp;</font>
<br><font size=2 face="Arial">The only down side here is that you tend to only get the basic Ccomp... about typical.</font>
<br><font size=3 face="Times New Roman">&nbsp;</font>
<br><font size=2 face="Arial">Anyway... just a pointer to a different direction if its an option for you. The software and equipment is rather spendy.</font>
<br><font size=3 face="Times New Roman">&nbsp;</font>
<br><font size=2 face="Arial">Dekker</font>
<br><font size=3 face="Times New Roman">----- Original Message ----- </font>
<br><font size=3 face="Times New Roman"><b>From:</b> </font><a href=mailto:[email-masked]><font size=3 color=blue face="Times New Roman"><u>[email-masked]</u></font></a><font size=3 face="Times New Roman"> </font>
<br><font size=3 face="Times New Roman"><b>To:</b> </font><a href="mailto:[email-masked]"><font size=3 color=blue face="Times New Roman"><u>[email-masked]</u></font></a><font size=3 face="Times New Roman"> </font>
<br><font size=3 face="Times New Roman"><b>Cc:</b> </font><a href=mailto:[email-masked]><font size=3 color=blue face="Times New Roman"><u>[email-masked]</u></font></a><font size=3 face="Times New Roman"> </font>
<br><font size=3 face="Times New Roman"><b>Sent:</b> Wednesday, August 06, 2003 2:25 AM</font>
<br><font size=3 face="Times New Roman"><b>Subject:</b> [IBIS-Users] How to determine Ccomp</font>
<br>
<br><font size=2 face="sans-serif"><br>
Dear IBIS collegues,</font><font size=3 face="Times New Roman"> <br>
</font><font size=2 face="sans-serif"><br>
What is the best way to determine Ccomp?</font><font size=3 face="Times New Roman"> </font><font size=2 face="sans-serif"><br>
Basically there are two ways: applying a ramp to the output terminal and calculate Ccomp from the slew-rate, or connecting an inductor to the output and calculate the Ccomp from the resonace frequency.</font><font size=3 face="Times New Roman"> </font><font size=2 face="sans-serif"><br>
Which method gives the best results? &gt; always, or application dependent?</font><font size=3 face="Times New Roman"> </font><font size=2 face="sans-serif"><br>
How is this done for differential outputs. Outputs like LVDS have internal feedback loops to control the common level. Must something be done with the &quot;other&quot; output? Is the peaking a reliable measure for the value of Ccomp, or may the added inductor shift the poles and zeros of the feedback buffer due this load causing a peaking that is not just the parallel connection of Ccomp and the test inductor?</font><font size=3 face="Times New Roman"> <br>
</font><font size=2 face="sans-serif"><br>
With kind regards,</font><font size=3 face="Times New Roman"> <br>
</font><font size=2 face="sans-serif"><br>
<br>
Ir. Erik van der Ven<br>
Room DB1032<br>
Business Line Networking Infrastructure<br>
Philips Semiconductors BV<br>
Gerstweg 2<br>
6534 AE Nijmegen<br>
The Netherlands<br>
Phone: +31-24-3534334</font>
<br>
<br>
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------------------------------

Date: Thu, 7 Aug 2003 11:15:43 -0400
From: "Mike LaBonte" <[email-masked]>
Subject: RE: [IBIS-Users] How to determine C_comp

The HSPICE manual gives a circuit example of the Frequency Domain imaginary
current method in the Buffer Characterization section, by the way.

Mike LaBonte

- -----Original Message-----
From: [email-masked] [mailto:[email-masked]]On Behalf Of
Muranyi, Arpad
Sent: Wednesday, August 06, 2003 4:24 PM
To: [email-masked]
Subject: RE: [IBIS-Users] How to determine C_comp

I know of about six methods to measure C_comp:

•RC time constant with a step function
•does not show voltage or frequency dependencies
•Time Domain forced saw tooth voltage
•can provide voltage dependent capacitance curves
•does not show frequency dependence
•TDR technique (Time Domain)
•does not show voltage or frequency dependencies
•Frequency Domain sweep with tank circuit
•can provide voltage dependent capacitance curves
•does not show frequency dependence(?)
•Frequency Domain imaginary current
•can provide voltage and frequency dependent capacitance curves
•shows frequency dependence very well
•Frequency Domain pole/zero method
•See BIRD 79 on IBIS web page for details

Arpad Muranyi
Intel Corporation
================================================

- -----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Wednesday, August 06, 2003 2:25 AM
To: [email-masked]
Cc: [email-masked]
Subject: [IBIS-Users] How to determine Ccomp

Dear IBIS collegues,

What is the best way to determine Ccomp?
Basically there are two ways: applying a ramp to the output terminal and
calculate Ccomp from the slew-rate, or connecting an inductor to the output
and calculate the Ccomp from the resonace frequency.
Which method gives the best results? > always, or application dependent?
How is this done for differential outputs. Outputs like LVDS have internal
feedback loops to control the common level. Must something be done with the
"other" output? Is the peaking a reliable measure for the value of Ccomp, or
may the added inductor shift the poles and zeros of the feedback buffer due
this load causing a peaking that is not just the parallel connection of
Ccomp and the test inductor?

With kind regards,

Ir. Erik van der Ven
Room DB1032
Business Line Networking Infrastructure
Philips Semiconductors BV
Gerstweg 2
6534 AE Nijmegen
The Netherlands
Phone: +31-24-3534334

|------------------------------------------------------------------
|For help or to subscribe/unsubscribe, email [email-masked]
|with just the appropriate command message(s) in the body:
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------------------------------

Date: Thu, 7 Aug 2003 10:20:16 -0700
From: "Eric Hsu" <[email-masked]>
Subject: [IBIS-Users] R/L/C_pin issue

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Hi IBIS expert,

When editing R/L/C_pin of ibis model, should I need to consider the =
connection from die to board? such as flip-chip BGA case:"pad --> RDL =
- --> bump --> package ( trace ) --> ball"?
If true, what's the reasonable way to consider about ball portion? My =
point is because it is the interface between chip and board. People may =
take this portion as part of board trace.

Best Regards,

Eric Hsu
Interface Technologies
NetLogic Microsystems, Inc.
450 National Ave.
Mountain View, CA 94043
650-961-6676 x198
This e-mail contains NetLogic Microsystems, Inc. Confidential =
information

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------------------------------

Date: Thu, 07 Aug 2003 18:18:47 -0700
From: Bob Ross <[email-masked]>
Subject: [IBIS-Users] BIRD82.1 Clarification of Clamp Table Use

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To IBIS Committee:

BIRD82.1 by Lynne Green and Bob Haller is attached for review.

Bob

- -- 
Bob Ross
Teraspeed Consulting Group LLC     Teraspeed Consulting Group LLC
2926 SE Yamhill St.                Device Modeling Division
Portland, OR 97214                 13610 SW Harness Lane
503-239-5536                       Beaverton, OR 97008
http://www.teraspeed.com           503-430-1065
[email-masked]                  503-246-8048 Direct

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 filename="BIRD82.1.txt"

****************************************************************************
****************************************************************************
                       Buffer Issue Resolution Document  (BIRD)

BIRD ID#:       82.1
ISSUE TITLE:    Clarification of Clamp Table Use
REQUESTOR:      Lynne Green, Cadence, and Robert Haller, SiSoft
DATE SUBMITTED: June 27, 2003, August 7, 2003
DATE ACCEPTED BY IBIS OPEN FORUM:  Pending

****************************************************************************
****************************************************************************

STATEMENT OF THE ISSUE:

Double-counting of clamp currents is the result of confusion over how the
clamp currents are summed by the tools.  Model makers are often unsure if
clamps are always active, or whether the [Power Clamp] works only with the
[Pullup] and the [GND Clamp] only with the [Pulldown].  This is difficult,
if not impossible, to detect with a parser.

This issue can be resolved by clarification of the text under
|    Keywords:  [Pulldown], [Pullup], [GND Clamp], [POWER Clamp]

****************************************************************************

STATEMENT OF THE RESOLVED SPECIFICATIONS:

Old text:
|         It is assumed that the simulator sums the clamp tables
|         together with the appropriate [Pullup] or [Pulldown] table
|         when a buffer is driving high or low, respectively.  From this
|         assumption and the nature of 3-statable buffers, it follows
|         that the data in the clamping table sections are handled as
|         constantly present tables and the [Pullup] and [Pulldown]
|         tables are used only when needed in the simulation.
|

Proposed text:
|         It is intended that both clamp tables are summed together
|         and then added to the appropriate [Pullup] or [Pulldown]
|         table when a buffer is driving high or low, respectively.
|
|         From this assumption and the nature of 3-statable buffers,
|         it follows that the data in the clamping table sections are
|         handled as constantly present tables and the [Pullup] and
|         [Pulldown] tables are used only when needed in the simulation.
|

****************************************************************************

ANALYSIS PATH/DATA THAT LED TO SPECIFICATION:

Comments from members of the Quality committee, as well as others,
indicated that some models double-count clamp currents.

****************************************************************************

ANY OTHER BACKGROUND INFORMATION:

Initially, it was suggested that this be detected by the parser, but
it was decided that this was too difficult.  This led to further
discussion of why double-counting occurred, and how clarification of
the spec could help address the issue.

****************************************************************************

- --------------090607040305050902040500--

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------------------------------

Date: Fri, 8 Aug 2003 09:29:38 -0700 
From: "deBurgh, Guy" <[email-masked]>
Subject: [IBIS-Users] BIRD74.6 EMI Parameters

To the IBIS Committee.

BIRD 74 has been updated. Briefly the changes are:

1) Improved example, better clarification of syntax, and grammar
corrections.
   The technical content has not been affected.

Guy de Burgh
Mentor Graphics

****************************************************************************
**
****************************************************************************
**

BIRD ID#:        74.6
ISSUE TITLE:     EMI Parameters
REQUESTER:       Guy de Burgh, Mentor Graphics
DATE SUBMITTED:  3/19/02, 5/31/02, /9/16/02, 4/30/03, 5/21/03, 7/18/03,
                 8/08/03
DATE ACCEPTED BY IBIS OPEN FORUM: Pending

****************************************************************************
**
****************************************************************************
**

STATEMENT OF THE ISSUE:

Additional parameters required for EMI analysis.
All these parameters are optional.

****************************************************************************
**

STATEMENT OF THE RESOLVED SPECIFICATIONS:

The following changes are proposed:

****************************************************************************
**

Changes and additions to the IBIS Specification are shown by the |* lines.
Examples are shown as they would be seen in a specification.

|===========================================================================
==
|===========================================================================
==
|
|                                 Section 10
|
|                        E M I   P A R A M E T E R S
|
|===========================================================================
==
|
| There are two sections here: one for a [Component] and one for a [Model].
|
|===========================================================================
==
|===========================================================================
==
|
| This section describes the structure of the EMI parameters under a
| top-level [Component] keyword. It is used to describe the EMI parameters
| associated with a [Component]. The parameters must be surrounded by
| the [Begin EMI Component] and [End EMI Component] keywords.
|
| The following set of keywords are defined:
|
|   [Begin EMI Component]
|   [End EMI Component]
|   [Pin EMI]
|   [Pin Domain EMI]
|
| The following set of subparameters are defined:
|
|   Domain
|   Cpd
|   C_Heatsink_gnd
|   C_Heatsink_float
|
|===========================================================================
==
|
|     Keyword:  [Begin EMI Component]
|    Required:  No
| Description:  Marks the beginning of the Component EMI parameters.
|  Sub-Params:  Domain, Cpd, C_Heatsink_gnd, C_Heatsink_float
|
|               Domain indicates whether the component is a digital, analog
|               or part digital part analog. Analog circuits are more
|               susceptible to low-level noise. Analog circuits operate at
|               very low signal levels (mV or uV) and can contain high gain
|               amplifiers. In contrast, digital circuits operate at
|               relatively large signal levels (compared to analog
circuits).
|
|               The syntax for Domain is:
|                  Domain   Domain_value
|
|               Where Domain_value is an enumerated argument, and is one of:
|                  Digital, Analog, Digital_analog
|
|               This subparameter is optional. If not entered the default
|               is Digital.
|
|               Cpd is the power dissipation capacitance parameter.
|               Cpd (Power Dissipation Capacitance) is the internal
parasitic
|               capacitance (e.g., gate-to-source and gate-to-drain
|               capacitance) plus the equivalent capacitance associated with
|               the through currents when both transistors (n-channel and
|               p-channel) are momentarily conducting.
|
|               It is typically for CMOS devices, and helps provide a more
|               accurate estimation of the power bus current, and therefore
|               the noise voltage on the power bus. Knowing the high
frequency
|               noise on the power bus (due to switching of digital
circuits)
|               the radiation can be calculated.
|
|               Sometimes Iccd (Dynamic power supply current) is found in
|               databooks. It is normally given for FACT families. Iccd is
|               specified in units of mA/MHz.
|
|               Cpd can be calculated from Iccd by the equation
|                  Cpd (nF) = Iccd (mA/MHz) / Vcc (V).
|
|               The syntax for Cpd is:
|                  Cpd = capacitance_value
|
|               The units of capacitance_value are Farads.
|
|               This subparameter is optional. If not entered the default
|               is 0.0F.
|
|               C_Heatsink_Float and C_Heatsink_Gnd define the heatsink
|               capacitance and connection conditions.
|               C_Heatsink_Float indicates that the heatsink is floating,
|               and C_Heatsink_Gnd indicates that the heatsink is grounded.
|
|               Internal currents inside a (high speed) IC can be closely
|               coupled onto a heatsink. As the heatsink is physically much
|               larger than the IC silicon chip and bond wires it is a more
|               efficient radiator. Knowing the capacitance of the heatsink
|               the radiated electric field can be estimated.
|
|               Only one of these subparameters can be defined. It is not
|               legal to define both. It is legal to omit both. In this case
|               it means that a heatsink is not present.
|
|               The subparameter takes one argument: the heatsink
capacitance
|
|               The syntax for Heatsink_cap is:
|                  C_Heatsink_float = capacitance_value
|                  C_Heatsink_gnd   = capacitance_value
|
|               The units for capacitance_value are Farads.
|
|               This subparameter is optional. If not entered the default
|               is that the component does not have a heatsink.
|
|===========================================================================
==
|
|     Keyword:  [End EMI Component]
|    Required:  No
| Description:  Marks the end of the Component EMI parameters.
|
|===========================================================================
==
|
|  Example:
|
[Begin EMI Component]
Domain           Digital
Cpd            = 6.4pF
C_Heatsink_gnd = 3.4pF
[End EMI Component]
|
|===========================================================================
==
|
|     Keyword:  [Pin EMI]
|    Required:  No
| Description:  Specifies the EMI parameters for a Pin.
|  Sub-Params:  domain_name, clock_div
| Usage Rules:  Each line must contain three columns.
|               The first column must contain the pin name. This pin name
|               must match a pin name in the [Pin] keyword. (The pin name
|               is the first column in the [Pin] record.)
|
|               The second column is the domain name. This specifies the
clock
|               domain for that pin. This is used by [Pin Domain EMI].
|               The field should be set to NA if unused.
|
|               The default for domain_name is that the percentage of power
|               used is 100%.
|
|               The third column is the clock division. This is the ratio
|               of the frequency at this pin to the reference pin. The
|               reference pin is always set to "1.0". The ratio is a
floating
|               point number. The choice of the reference in does not matter
|               as this information is pin to pin ratios. It is suggested
that
|               the pin with the maximum frequency is chosen as the
reference.
|               The field should be set to NA if unused.
|
|               The default for clock_div is 1.0
|
|               Column length limits are:
|                  pin_name      5 characters max
|                  domain_name  20 characters max
|                  clock_div     5 characters max
|
|               It is not a requirement to specify every pin. An undefined
|               pin will default to 100% power usage for Domain_name,
|               and 1.0 for clock_div.
|
|===========================================================================
=
|
|     Keyword:  [Pin Domain EMI]
|    Required:  No
| Description:  Specifies the percentage of power used in each clock domain.
|  Sub-Params:  percentage
| Usage Rules:  Each line must contain two columns.
|               The first column must contain the domain_name. This name
must
|               match a domain name in the [Pin EMI] keyword. (The domain
|               name is the second column in that record.)
|
|               The percentage represents a user definable percentage of the
|               power used by that domain. It is an integer in the range
|               0 < percentage =< 100
|
|               Column length limits are:
|                  domain_name  20 characters max
|                  percentage    5 characters max
|
|===========================================================================
==
|
|  Example:
|
[Begin EMI Component]
Domain          Digital
Cpd           = 6.4pF
|
[Pin EMI]   domain_name    clock_div
 4          MEM            0.5
 5          MEM            0.5
 7          NA             0.5           | domain_name defaults to 100%
 8          RIOG           NA            | clock_div defaults to 1.0
14          CPU            1.0
15          RIOG           0.5
|
[Pin Domain EMI]   percentage
 CPU               40
 MEM               30
 RIOG              30
|
[End EMI Component]
|
|===========================================================================
==
|===========================================================================
==
|
| This section describes the structure of the EMI parameters under a
| top-level [Model] keyword. It is used to describe the EMI parameters
| associated with a [Model]. The parameters must be surrounded by
| the [Begin EMI Model] and [End EMI Model] keywords.
|
| The following set of keywords are defined:
|
|   [Begin EMI Model]
|   [End EMI Model]
|
| The following set of subparameters are defined:
|
|   Model_emi_type
|   Model_Domain
|
|===========================================================================
==
|
|     Keyword:  [Begin EMI Model]
|    Required:  No
| Description:  Marks the beginning of the Model EMI parameters.
|  Sub-Params:  Model_emi_type, Domain
|
|               Model_emi_type indicates whether the model (for this pin) is
a
|               ferrite or not.
|
|               The syntax for Model_emi_type is:
|                  Model_emi_type   Model_emi_type_value
|
|               Where Model_emi_type_value is an enumerated argument, and is
|               one of:
|                  Ferrite, Not_a_ferrite
|
|               If not entered (the default) the model is Not_a_ferrite.
|
|               Model_Domain indicates whether the model is digital or
analog.
|               This is only used if the [Component EMI] Domain is set to
|               Digital_analog. If the [Component EMI] Domain is set to
|               anything else Model_Domain is ignored.
|
|               The syntax for Domain is:
|                  Model_Domain   Domain_value
|
|               Where Domain_value is one of:
|                  Digital, Analog
|
|               If not entered the default is to use the [Component EMI]
|               Domain setting and it's default.
|
|===========================================================================
==
|
|     Keyword:  [End EMI Model]
|    Required:  No
| Description:  Marks the end of the Model EMI parameters.
|
|===========================================================================
==
|
|---------------------------------------------------------------------------
- --
|
[Begin EMI Model]
Domain          Analog
Model_emi_type  Ferrite
[End EMI Model]
|
****************************************************************************
**

ANALYSIS PATH/DATA THAT LED TO SPECIFICATION:

EMI is becoming increasingly important in PCB design.
EMI simulation is not an exact science. The problem is too complicated
for today's computers. However being able to identify which signals
radiate more than others (relatively), and showing where the energy
flows in a system does help in identifying potential EMI problems.
No longer requiring absolute accuracy, but requiring relative accuracy,
makes the analysis considerably easier, and possible. The parameters
specified here are chosen for that purpose, and have been specifically
chosen as they are readily available in data books in order to make it
easier to create models.

****************************************************************************
**

ANY OTHER BACKGROUND INFORMATION:

Presentations on this topic were given at the IBIS Summit Meeting
at DAC on June 21, 2001, and at DesignCon on January 28, 2002.

****************************************************************************
**
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------------------------------

Date: Mon, 11 Aug 2003 11:00:37 +0200
From: [email-masked]
Subject: [IBIS-Users] pullup/pulldown range LVDS

This is a multipart message in MIME format.
- --=_alternative 0031B6BCC1256D7F_=
Content-Type: text/plain; charset="us-ascii"

Dear IBIS users,

For ECL the pullup/pulldown curves only have to cover the 0-2.2V range 
(relative to Vcc). This is because of the limited voltage swing, which is 
centered around a DC voltage far away from the supply rails. 
How about LVDS? It has a similar output swing. Is it needed to cover the 
"regular" voltage range of -3.3-6.6V (for 3.3V supply)? It's rather a 
waste of accuracy for the typical operation area (less points remain). 

With kind regards,

Ir. Erik van der Ven
Room DB1032
Business Line Networking Infrastructure
Philips Semiconductors BV
Gerstweg 2
6534 AE Nijmegen
The Netherlands
Phone: +31-24-3534334
- --=_alternative 0031B6BCC1256D7F_=
Content-Type: text/html; charset="us-ascii"

<br><font size=2 face="sans-serif">Dear IBIS users,</font>
<br>
<br><font size=2 face="sans-serif">For ECL the pullup/pulldown curves only have to cover the 0-2.2V range (relative to Vcc). This is because of the limited voltage swing, which is centered around a DC voltage far away from the supply rails. </font>
<br><font size=2 face="sans-serif">How about LVDS? It has a similar output swing. Is it needed to cover the &quot;regular&quot; voltage range of -3.3-6.6V (for 3.3V supply)? It's rather a waste of accuracy for the typical operation area (less points remain). </font>
<br>
<br><font size=2 face="sans-serif">With kind regards,</font>
<br>
<br><font size=2 face="sans-serif"><br>
Ir. Erik van der Ven<br>
Room DB1032<br>
Business Line Networking Infrastructure<br>
Philips Semiconductors BV<br>
Gerstweg 2<br>
6534 AE Nijmegen<br>
The Netherlands<br>
Phone: +31-24-3534334</font>
- --=_alternative 0031B6BCC1256D7F_=--
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|with just the appropriate command message(s) in the body:
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|
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|  http://www.eda.org/pub/ibis/email/          E-mail since 1993

------------------------------

Date: Mon, 11 Aug 2003 10:42:02 -0400
From: "Allen Chao" <[email-masked]>
Subject: [IBIS-Users] for the minimum and maximum data

Hi IBIS experts,
For the minimum and maximum datas, do we only consider the temperature and
the voltage source (90% to 110%)? or we should consider the slow/fast
corners for the resistors and mos transistors if we have those libraries
available?

Thanks in advance,

Allen

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------------------------------

Date: Mon, 11 Aug 2003 13:06:06 -0400
From: "Lynne Green" <[email-masked]>
Subject: RE: [IBIS-Users] pullup/pulldown range LVDS

This is a multi-part message in MIME format.

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	charset="us-ascii"
Content-Transfer-Encoding: quoted-printable

Hello, Erik,
=20
One would normally add one point at each end outside of the normal
operating
range (using the same current as the normal operating endpoint).  This
only
"costs" two points of the 100 allowed in IBIS 3.2, so there is no
significant loss
in accuracy.
=20
This does two things:
1) Allows the simulator tool to search the entire -Vcc,+2Vcc range when=20
   performing convergence phase, resulting in faster convergence.
2) Allows the IBIS file to pass the IBIS parser.
=20
| Example with 12mA end points in I-V data:
- -3.3V   -12m   | dummy end point
0.4V    -12m   | end point of actual operating region
                     | normal data, up to 96 more lines
1.6V     12m   | end point of actual operating region
6.6V     12m   | dummy end point
=20
Best regards,
Lynne
=20
- -----Original Message-----
From: [email-masked] [mailto:[email-masked]]

Sent: Monday, August 11, 2003 2:01 AM
To: [email-masked]
Subject: [IBIS-Users] pullup/pulldown range LVDS

Dear IBIS users,=20

For ECL the pullup/pulldown curves only have to cover the 0-2.2V range
(relative to Vcc). This is because of the limited voltage swing, which
is centered around a DC voltage far away from the supply rails.=20
How about LVDS? It has a similar output swing. Is it needed to cover the
"regular" voltage range of -3.3-6.6V (for 3.3V supply)? It's rather a
waste of accuracy for the typical operation area (less points remain).=20

With kind regards,=20

Ir. Erik van der Ven
Room DB1032
Business Line Networking Infrastructure
Philips Semiconductors BV
Gerstweg 2
6534 AE Nijmegen
The Netherlands
Phone: +31-24-3534334

- ------_=_NextPart_001_01C3602A.DA493B92
Content-Type: text/html;
	charset="us-ascii"
Content-Transfer-Encoding: quoted-printable

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD><TITLE>Message</TITLE>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Dus-ascii">
<META content=3D"MSHTML 6.00.2713.1100" name=3DGENERATOR></HEAD>
<BODY>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =
size=3D2>Hello,=20
Erik,</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =

size=3D2></FONT></SPAN>&nbsp;</DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =

size=3D2>One&nbsp;would normally add one point at each end outside of =
the normal=20
operating</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =
size=3D2>range=20
(using the same current as the normal operating endpoint).&nbsp; This=20
only</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =

size=3D2>"costs" two points of the 100 allowed in IBIS 3.2, so there is =
no=20
significant loss</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =
size=3D2>in=20
accuracy.</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =

size=3D2></FONT></SPAN>&nbsp;</DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =
size=3D2>This=20
does two things:</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =
size=3D2>1)=20
Allows the simulator tool to search the entire -Vcc,+2Vcc range when=20
</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =

size=3D2>&nbsp;&nbsp; performing&nbsp;convergence phase, resulting in=20
faster&nbsp;</FONT></SPAN><SPAN class=3D074355016-11082003><FONT =
face=3DArial=20
color=3D#0000ff size=3D2>convergence.</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =
size=3D2>2)=20
Allows the IBIS file to pass the IBIS parser.</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =

size=3D2></FONT></SPAN>&nbsp;</DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =
size=3D2>|=20
Example with 12mA end points in I-V data:</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =

size=3D2>-3.3V&nbsp; &nbsp;-12m&nbsp;&nbsp; | dummy end =
point</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =

size=3D2>0.4V&nbsp;&nbsp;&nbsp; -12m&nbsp;&nbsp; | end point of actual =
operating=20
region</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =

size=3D2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs=
p;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=20
| normal data, up to 96 more lines</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =

size=3D2>1.6V&nbsp;&nbsp;&nbsp; &nbsp;12m&nbsp;&nbsp; | end point of =
actual=20
operating region</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =

size=3D2>6.6V&nbsp;&nbsp; &nbsp; 12m&nbsp;&nbsp; | dummy end=20
point</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =

size=3D2></FONT></SPAN>&nbsp;</DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =
size=3D2>Best=20
regards,</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =

size=3D2>Lynne</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT face=3DArial color=3D#0000ff =

size=3D2></FONT></SPAN>&nbsp;</DIV>
<DIV></DIV>
<DIV class=3DOutlookMessageHeader lang=3Den-us dir=3Dltr =
align=3Dleft><FONT face=3DTahoma=20
size=3D2>-----Original Message-----<BR><B>From:</B> =
[email-masked]=20
[mailto:[email-masked]] <BR><B>Sent:</B> Monday, August =
11, 2003=20
2:01 AM<BR><B>To:</B> [email-masked]<BR><B>Subject:</B> [IBIS-Users] =

pullup/pulldown range LVDS<BR><BR></FONT></DIV><BR><FONT =
face=3Dsans-serif=20
size=3D2>Dear IBIS users,</FONT> <BR><BR><FONT face=3Dsans-serif =
size=3D2>For ECL the=20
pullup/pulldown curves only have to cover the 0-2.2V range (relative to =
Vcc).=20
This is because of the limited voltage swing, which is centered around a =
DC=20
voltage far away from the supply rails. </FONT><BR><FONT =
face=3Dsans-serif=20
size=3D2>How about LVDS? It has a similar output swing. Is it needed to =
cover the=20
"regular" voltage range of -3.3-6.6V (for 3.3V supply)? It's rather a =
waste of=20
accuracy for the typical operation area (less points remain).=20
</FONT><BR><BR><FONT face=3Dsans-serif size=3D2>With kind =
regards,</FONT>=20
<BR><BR><FONT face=3Dsans-serif size=3D2><BR>Ir. Erik van der =
Ven<BR>Room=20
DB1032<BR>Business Line Networking Infrastructure<BR>Philips =
Semiconductors=20
BV<BR>Gerstweg 2<BR>6534 AE Nijmegen<BR>The Netherlands<BR>Phone:=20
+31-24-3534334</FONT></BODY></HTML>
=00
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|
|  help
|  subscribe   ibis       <optional e-mail address, if different>
|  subscribe   ibis-users <optional e-mail address, if different>
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|  unsubscribe ibis-users <optional e-mail address, if different>
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|IBIS reflector archives exist under:
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|  http://www.eda.org/pub/ibis/users_archive/  Recent
|  http://www.eda.org/pub/ibis/email/          E-mail since 1993

------------------------------

Date: Wed, 13 Aug 2003 15:09:19 +0100
From: Gavin Cosgrave <[email-masked]>
Subject: [IBIS-Users] IBIS Temperature range

Hi all,
	I am generating an IBIS model for a part with a Vdd spec of
2.5 to 5.5 Volts. My question is whether I should generate two IBIS
models, one with Voltage Range 4.5, 5, 5.5, and the other with 2.5,
2.7, 3?
	
	The reason I ask is that if someone is using a Vdd=5V system,
and if I extract the model with voltage range 2.5, 5, 5.5, the min
will be well below anything they ever see.
	
	Apologies if this question has already been answered, but I
can't find anything in the archive.

Thanks,
Gavin.

- -- 
Gavin Cosgrave,
Analog Devices, Building 2200, Cork Airport Business Park,
Cork, Ireland.
Tel:+353-21-4917906
Internal:6021-7906
|------------------------------------------------------------------
|For help or to subscribe/unsubscribe, email [email-masked]
|with just the appropriate command message(s) in the body:
|
|  help
|  subscribe   ibis       <optional e-mail address, if different>
|  subscribe   ibis-users <optional e-mail address, if different>
|  unsubscribe ibis       <optional e-mail address, if different>
|  unsubscribe ibis-users <optional e-mail address, if different>
|
|or email a written request to [email-masked].
|
|IBIS reflector archives exist under:
|
|  http://www.eda.org/pub/ibis/email_archive/  Recent
|  http://www.eda.org/pub/ibis/users_archive/  Recent
|  http://www.eda.org/pub/ibis/email/          E-mail since 1993

------------------------------

Date: Wed, 13 Aug 2003 13:59:41 -0400
From: "Mike LaBonte" <[email-masked]>
Subject: RE: [IBIS-Users] IBIS Temperature range

In theory an IBIS model produced for one supply voltage works over a range
of supply voltages. In practice, you will probably find that producing the
same model using s2ibis2 with different supply voltages yields different
models. I prefer not to use an IBIS model at any voltage other than the one
it was produced for.

Mike LaBonte

- -----Original Message-----
From: [email-masked] [mailto:[email-masked]]On
Behalf Of Gavin Cosgrave
Sent: Wednesday, August 13, 2003 10:09 AM
To: [email-masked]
Subject: [IBIS-Users] IBIS Temperature range

Hi all,
	I am generating an IBIS model for a part with a Vdd spec of
2.5 to 5.5 Volts. My question is whether I should generate two IBIS
models, one with Voltage Range 4.5, 5, 5.5, and the other with 2.5,
2.7, 3?

	The reason I ask is that if someone is using a Vdd=5V system,
and if I extract the model with voltage range 2.5, 5, 5.5, the min
will be well below anything they ever see.

	Apologies if this question has already been answered, but I
can't find anything in the archive.

Thanks,
Gavin.

- --
Gavin Cosgrave,
Analog Devices, Building 2200, Cork Airport Business Park,
Cork, Ireland.
Tel:+353-21-4917906
Internal:6021-7906
|------------------------------------------------------------------
|For help or to subscribe/unsubscribe, email [email-masked]
|with just the appropriate command message(s) in the body:
|
|  help
|  subscribe   ibis       <optional e-mail address, if different>
|  subscribe   ibis-users <optional e-mail address, if different>
|  unsubscribe ibis       <optional e-mail address, if different>
|  unsubscribe ibis-users <optional e-mail address, if different>
|
|or email a written request to [email-masked].
|
|IBIS reflector archives exist under:
|
|  http://www.eda.org/pub/ibis/email_archive/  Recent
|  http://www.eda.org/pub/ibis/users_archive/  Recent
|  http://www.eda.org/pub/ibis/email/          E-mail since 1993

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|For help or to subscribe/unsubscribe, email [email-masked]
|with just the appropriate command message(s) in the body:
|
|  help
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|
|or email a written request to [email-masked].
|
|IBIS reflector archives exist under:
|
|  http://www.eda.org/pub/ibis/email_archive/  Recent
|  http://www.eda.org/pub/ibis/users_archive/  Recent
|  http://www.eda.org/pub/ibis/email/          E-mail since 1993

------------------------------

Date: Wed, 13 Aug 2003 16:37:50 -0400
From: "Allen Chao" <[email-masked]>
Subject: RE: [IBIS-Users] IBIS model Error

This is a multi-part message in MIME format.

- ------=_NextPart_000_0007_01C361B9.3C85EDC0
Content-Type: text/plain;
	charset="us-ascii"
Content-Transfer-Encoding: 7bit

Hi IBIS experts,
I have the same problem as Muthu Lakshmi. I don't really understand how the
parser calculated the DC end points from the IV table... If anyone can
kindly show me how it works or know where to find the information on the
internet, it will be greatly appreciated.

Thanks in advance,

Allen Chao

  -----Original Message-----
  From: [email-masked] [mailto:[email-masked]]On Behalf
Of [email-masked]
  Sent: Monday, July 28, 2003 4:10 AM
  To: [email-masked]; [email-masked]
  Subject: Re: [IBIS-Users] IBIS model Error

  Hello Muthu Lakshmi,

  I think there is something wrong with your IBIS model. The DC end points
calculated from the I-V tables should match the V-T end points (logic
levels). If the error is within 2% you should get a warning, otherwise an
error. The difference you mention is very big.

  The DC end points are calculated from the I-V tables (therefore you don't
see the end points of the V-T table). The I-V tables are derived by sweeping
a voltage at the output and measuring the resulting current. By applying a
certain load the voltages from the logic high and low level are calculated
from the pull-up and pull-down curve (and of course they should be near the
waveform end point voltages). The V-T data is used to describe the
transition between the logic levels calculated from the I-V data.

  I would suggest that you contact Cypress to ask if this model is OK.

  With kind regards,

  Ir. Erik van der Ven
  Room DB1032
  Business Line Networking Infrastructure
  Philips Semiconductors BV
  Gerstweg 2
  6534 AE Nijmegen
  The Netherlands
  Phone: +31-24-3534334

        [email-masked]
        Sent by:
        [email-masked]

        07/28/03 05:32 AM

                To:        [email-masked]
                cc:        (bcc: Erik van der Ven/NYM/SC/PHILIPS)
                Subject:        [IBIS-Users] IBIS model Error
                Classification:

  Hi All,

  I need IBIS expert's advice on the following.

  I get the following warning when checking the IBIS model.

  Warning - Model bp_usb_hs: The [Rising Waveform]
       with [R_fixture]=45 Ohms and [V_fixture]=0V
       has TYP column DC endpoints of  0.00V and  0.38v, but
       an equivalent load applied to the model's I-V tables yields
       different voltages ( 1.14V and  1.06V),
       a difference of 99.99% and 64.28%, respectively.

  Warning - Model bp_usb_hs: The [Falling Waveform]
       with [R_fixture]=45 Ohms and [V_fixture]=0V
       has TYP column DC endpoints of  0.00V and  0.38v, but
       an equivalent load applied to the model's I-V tables yields
       different voltages ( 1.14V and  1.06V),
       a difference of 99.99% and 64.28%, respectively.

  Warning - Model bp_usb_hs: The [Rising Waveform]
       with [R_fixture]=45 Ohms and [V_fixture_min]=0V
       has MIN column DC endpoints of  0.00V and  0.37v, but
       an equivalent load applied to the model's I-V tables yields
       different voltages ( 1.09V and  0.93V),
       a difference of 99.99% and 60.23%, respectively.

  Warning - Model bp_usb_hs: The [Falling Waveform]
       with [R_fixture]=45 Ohms and [V_fixture_min]=0V
       has MIN column DC endpoints of  0.00V and  0.37v, but
       an equivalent load applied to the model's I-V tables yields
       different voltages ( 1.09V and  0.93V),
       a difference of 99.99% and 60.23%, respectively.

  Warning - Model bp_usb_hs: The [Rising Waveform]
       with [R_fixture]=45 Ohms and [V_fixture_max]=0V
       has MAX column DC endpoints of  0.00V and  0.39v, but
       an equivalent load applied to the model's I-V tables yields
       different voltages ( 1.77V and  1.83V),
       a difference of 100.00% and 78.72%, respectively.

  Warning - Model bp_usb_hs: The [Falling Waveform]
       with [R_fixture]=45 Ohms and [V_fixture_max]=0V
       has MAX column DC endpoints of  0.00V and  0.38v, but
       an equivalent load applied to the model's I-V tables yields
       different voltages ( 1.77V and  1.83V),
       a difference of 100.00% and 79.26%, respectively.

  Please tell me the impact of this warning in simulation. I use XTK for the
simulation. Eventhough the rise and fall VT curve values range from 0V to
0.38V in the IBIS model, I get 1.04V to 1.14V wave form. How is this related
with this. I am using Cypress "CY7C65640" hub controller's IBIS model.

  Awaiting your earliest reply.

  Note: One IBIS parser gives the above warnings and another parser gives
them as Errors.
         I do not know whether files can be attached with this mail. If it
is OK, I can send  the IBIS model.

  thanks & regards
  K.Muthu Lakshmi (KML)

  SCM Microsystems (India) Pvt. Ltd.
  email: [email-masked]
  Web: www.scmmicro.com

- ------=_NextPart_000_0007_01C361B9.3C85EDC0
Content-Type: text/html;
	charset="us-ascii"
Content-Transfer-Encoding: quoted-printable

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Dus-ascii">
<META content=3D"MSHTML 6.00.2800.1170" name=3DGENERATOR></HEAD>
<BODY>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN =
class=3D129252920-13082003>Hi=20
IBIS experts,</SPAN></FONT></DIV>
<DIV><FONT color=3D#0000ff size=3D2><SPAN =
class=3D129252920-13082003><FONT=20
face=3DArial>I have the same problem as&nbsp;Muthu Lakshmi. I don't =
really=20
understand how the parser calculated the&nbsp;DC end points from the IV =
table...=20
If anyone can kindly show me how it works or know where to find the =
information=20
on the internet,&nbsp;it will be greatly =
appreciated.</FONT></SPAN></FONT></DIV>
<DIV><FONT color=3D#0000ff size=3D2><SPAN=20
class=3D129252920-13082003></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT color=3D#0000ff size=3D2><SPAN =
class=3D129252920-13082003><FONT=20
face=3DArial>Thanks&nbsp;in advance,</FONT></SPAN></FONT></DIV>
<DIV><FONT color=3D#0000ff size=3D2><SPAN=20
class=3D129252920-13082003></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT color=3D#0000ff size=3D2><SPAN =
class=3D129252920-13082003><FONT=20
face=3DArial>Allen Chao</FONT>&nbsp;</SPAN></FONT></DIV>
<DIV><FONT color=3D#0000ff size=3D2><SPAN =
class=3D129252920-13082003><FONT=20
face=3D"Lucida Sans Unicode"></FONT></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=3D"Lucida Sans Unicode" color=3D#0000ff size=3D2><SPAN=20
class=3D129252920-13082003></SPAN></FONT>&nbsp;</DIV>
<BLOCKQUOTE>
  <DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
  size=3D2>-----Original Message-----<BR><B>From:</B> =
[email-masked]=20
  [mailto:[email-masked]]<B>On Behalf Of=20
  </B>[email-masked]<BR><B>Sent:</B> Monday, July 28, 2003 =
4:10=20
  AM<BR><B>To:</B> [email-masked];=20
  [email-masked]<BR><B>Subject:</B> Re: [IBIS-Users] IBIS model=20
  Error<BR><BR></FONT></DIV><BR><FONT face=3Dsans-serif size=3D2>Hello =
Muthu=20
  Lakshmi,</FONT> <BR><BR><FONT face=3Dsans-serif size=3D2>I think there =
is=20
  something wrong with your IBIS model. The DC end points calculated =
from the=20
  I-V tables should match the V-T end points (logic levels). If the =
error is=20
  within 2% you should get a warning, otherwise an error. The difference =
you=20
  mention is very big.</FONT> <BR><BR><FONT face=3Dsans-serif =
size=3D2>The DC end=20
  points are calculated from the I-V tables (therefore you don't see the =
end=20
  points of the V-T table). The I-V tables are derived by sweeping a =
voltage at=20
  the output and measuring the resulting current. By applying a certain =
load the=20
  voltages from the logic high and low level are calculated from the =
pull-up and=20
  pull-down curve (and of course they should be near the waveform end =
point=20
  voltages). The V-T data is used to describe the transition between the =
logic=20
  levels calculated from the I-V data.</FONT> <BR><BR><FONT =
face=3Dsans-serif=20
  size=3D2>I would suggest that you contact Cypress to ask if this model =
is=20
  OK.</FONT> <BR><BR><BR><FONT face=3Dsans-serif size=3D2>With kind =
regards,</FONT>=20
  <BR><BR><FONT face=3Dsans-serif size=3D2><BR>Ir. Erik van der =
Ven<BR>Room=20
  DB1032<BR>Business Line Networking Infrastructure<BR>Philips =
Semiconductors=20
  BV<BR>Gerstweg 2<BR>6534 AE Nijmegen<BR>The Netherlands<BR>Phone:=20
  +31-24-3534334</FONT> <BR><BR><BR>
  <TABLE width=3D"100%">
    <TBODY>
    <TR vAlign=3Dtop>
      <TD>
      <TD><BR><BR><BR><BR><BR><FONT face=3Dsans-serif=20
        size=3D1><B>[email-masked]</B></FONT>=20
        <P><FONT face=3Dsans-serif size=3D1>Sent by: </FONT><BR><FONT=20
        face=3Dsans-serif size=3D1>[email-masked]</FONT>=20
        <P><FONT face=3Dsans-serif size=3D1>07/28/03 05:32 AM</FONT> =
<BR></P>
      <TD><FONT face=3DArial size=3D1>&nbsp; &nbsp; &nbsp; &nbsp; =
</FONT><BR><FONT=20
        face=3Dsans-serif size=3D1>&nbsp; &nbsp; &nbsp; &nbsp; To: =
&nbsp; &nbsp;=20
        &nbsp; &nbsp;[email-masked]</FONT> <BR><FONT =
face=3Dsans-serif=20
        size=3D1>&nbsp; &nbsp; &nbsp; &nbsp; cc: &nbsp; &nbsp; &nbsp; =
&nbsp;(bcc:=20
        Erik van der Ven/NYM/SC/PHILIPS)</FONT> <BR><FONT =
face=3Dsans-serif=20
        size=3D1>&nbsp; &nbsp; &nbsp; &nbsp; Subject: &nbsp; &nbsp; =
&nbsp;=20
        &nbsp;[IBIS-Users] IBIS model Error</FONT>=20
        <P><FONT face=3Dsans-serif size=3D1>&nbsp; &nbsp; &nbsp; &nbsp;=20
        Classification: &nbsp; &nbsp; &nbsp; &nbsp;</FONT>=20
  <BR></P></TR></TBODY></TABLE><BR><BR><BR><FONT face=3Dsans-serif =
size=3D2><BR>Hi=20
  All,</FONT><FONT face=3D"Times New Roman" size=3D3> <BR></FONT><FONT=20
  face=3Dsans-serif size=3D2><BR>I need IBIS expert's advice on the=20
  following.</FONT><FONT face=3D"Times New Roman" size=3D3> =
<BR></FONT><FONT=20
  face=3Dsans-serif size=3D2><BR>I get the following warning when =
checking the IBIS=20
  model. </FONT><FONT face=3D"Times New Roman" size=3D3><BR></FONT><FONT =

  face=3Dsans-serif color=3Dblue size=3D2><BR>Warning - Model bp_usb_hs: =
The [Rising=20
  Waveform] <BR>&nbsp; &nbsp; &nbsp;with [R_fixture]=3D45 Ohms and=20
  [V_fixture]=3D0V</FONT><FONT face=3D"Times New Roman" size=3D3> =
</FONT><FONT=20
  face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; &nbsp;has =
TYP column DC=20
  endpoints of &nbsp;0.00V and &nbsp;0.38v, but</FONT><FONT=20
  face=3D"Times New Roman" size=3D3> </FONT><FONT face=3Dsans-serif =
color=3Dblue=20
  size=3D2><BR>&nbsp; &nbsp; &nbsp;an equivalent load applied to the =
model's I-V=20
  tables yields</FONT><FONT face=3D"Times New Roman" size=3D3> =
</FONT><FONT=20
  face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; =
&nbsp;different voltages (=20
  1.14V and &nbsp;1.06V),</FONT><FONT face=3D"Times New Roman" size=3D3> =

  </FONT><FONT face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; =
&nbsp;a=20
  difference of 99.99% and 64.28%, respectively.</FONT><FONT=20
  face=3D"Times New Roman" size=3D3> <BR></FONT><FONT face=3Dsans-serif =
color=3Dblue=20
  size=3D2><BR>Warning - Model bp_usb_hs: The [Falling Waveform] =
<BR>&nbsp; &nbsp;=20
  &nbsp;with [R_fixture]=3D45 Ohms and [V_fixture]=3D0V</FONT><FONT=20
  face=3D"Times New Roman" size=3D3> </FONT><FONT face=3Dsans-serif =
color=3Dblue=20
  size=3D2><BR>&nbsp; &nbsp; &nbsp;has TYP column DC endpoints of =
&nbsp;0.00V and=20
  &nbsp;0.38v, but</FONT><FONT face=3D"Times New Roman" size=3D3> =
</FONT><FONT=20
  face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; &nbsp;an =
equivalent load=20
  applied to the model's I-V tables yields</FONT><FONT face=3D"Times New =
Roman"=20
  size=3D3> </FONT><FONT face=3Dsans-serif color=3Dblue =
size=3D2><BR>&nbsp; &nbsp;=20
  &nbsp;different voltages ( 1.14V and &nbsp;1.06V),</FONT><FONT=20
  face=3D"Times New Roman" size=3D3> </FONT><FONT face=3Dsans-serif =
color=3Dblue=20
  size=3D2><BR>&nbsp; &nbsp; &nbsp;a difference of 99.99% and 64.28%,=20
  respectively.</FONT><FONT face=3D"Times New Roman" size=3D3> =
<BR></FONT><FONT=20
  face=3Dsans-serif color=3Dblue size=3D2><BR>Warning - Model bp_usb_hs: =
The [Rising=20
  Waveform] <BR>&nbsp; &nbsp; &nbsp;with [R_fixture]=3D45 Ohms and=20
  [V_fixture_min]=3D0V</FONT><FONT face=3D"Times New Roman" size=3D3> =
</FONT><FONT=20
  face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; &nbsp;has =
MIN column DC=20
  endpoints of &nbsp;0.00V and &nbsp;0.37v, but</FONT><FONT=20
  face=3D"Times New Roman" size=3D3> </FONT><FONT face=3Dsans-serif =
color=3Dblue=20
  size=3D2><BR>&nbsp; &nbsp; &nbsp;an equivalent load applied to the =
model's I-V=20
  tables yields</FONT><FONT face=3D"Times New Roman" size=3D3> =
</FONT><FONT=20
  face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; =
&nbsp;different voltages (=20
  1.09V and &nbsp;0.93V),</FONT><FONT face=3D"Times New Roman" size=3D3> =

  </FONT><FONT face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; =
&nbsp;a=20
  difference of 99.99% and 60.23%, respectively.</FONT><FONT=20
  face=3D"Times New Roman" size=3D3> <BR></FONT><FONT face=3Dsans-serif =
color=3Dblue=20
  size=3D2><BR>Warning - Model bp_usb_hs: The [Falling Waveform] =
<BR>&nbsp; &nbsp;=20
  &nbsp;with [R_fixture]=3D45 Ohms and [V_fixture_min]=3D0V</FONT><FONT=20
  face=3D"Times New Roman" size=3D3> </FONT><FONT face=3Dsans-serif =
color=3Dblue=20
  size=3D2><BR>&nbsp; &nbsp; &nbsp;has MIN column DC endpoints of =
&nbsp;0.00V and=20
  &nbsp;0.37v, but</FONT><FONT face=3D"Times New Roman" size=3D3> =
</FONT><FONT=20
  face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; &nbsp;an =
equivalent load=20
  applied to the model's I-V tables yields</FONT><FONT face=3D"Times New =
Roman"=20
  size=3D3> </FONT><FONT face=3Dsans-serif color=3Dblue =
size=3D2><BR>&nbsp; &nbsp;=20
  &nbsp;different voltages ( 1.09V and &nbsp;0.93V),</FONT><FONT=20
  face=3D"Times New Roman" size=3D3> </FONT><FONT face=3Dsans-serif =
color=3Dblue=20
  size=3D2><BR>&nbsp; &nbsp; &nbsp;a difference of 99.99% and 60.23%,=20
  respectively.</FONT><FONT face=3D"Times New Roman" size=3D3> =
<BR></FONT><FONT=20
  face=3Dsans-serif color=3Dblue size=3D2><BR>Warning - Model bp_usb_hs: =
The [Rising=20
  Waveform] <BR>&nbsp; &nbsp; &nbsp;with [R_fixture]=3D45 Ohms and=20
  [V_fixture_max]=3D0V</FONT><FONT face=3D"Times New Roman" size=3D3> =
</FONT><FONT=20
  face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; &nbsp;has =
MAX column DC=20
  endpoints of &nbsp;0.00V and &nbsp;0.39v, but</FONT><FONT=20
  face=3D"Times New Roman" size=3D3> </FONT><FONT face=3Dsans-serif =
color=3Dblue=20
  size=3D2><BR>&nbsp; &nbsp; &nbsp;an equivalent load applied to the =
model's I-V=20
  tables yields</FONT><FONT face=3D"Times New Roman" size=3D3> =
</FONT><FONT=20
  face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; =
&nbsp;different voltages (=20
  1.77V and &nbsp;1.83V),</FONT><FONT face=3D"Times New Roman" size=3D3> =

  </FONT><FONT face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; =
&nbsp;a=20
  difference of 100.00% and 78.72%, respectively.</FONT><FONT=20
  face=3D"Times New Roman" size=3D3> <BR></FONT><FONT face=3Dsans-serif =
color=3Dblue=20
  size=3D2><BR>Warning - Model bp_usb_hs: The [Falling Waveform] =
<BR>&nbsp; &nbsp;=20
  &nbsp;with [R_fixture]=3D45 Ohms and [V_fixture_max]=3D0V</FONT><FONT=20
  face=3D"Times New Roman" size=3D3> </FONT><FONT face=3Dsans-serif =
color=3Dblue=20
  size=3D2><BR>&nbsp; &nbsp; &nbsp;has MAX column DC endpoints of =
&nbsp;0.00V and=20
  &nbsp;0.38v, but</FONT><FONT face=3D"Times New Roman" size=3D3> =
</FONT><FONT=20
  face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; &nbsp;an =
equivalent load=20
  applied to the model's I-V tables yields</FONT><FONT face=3D"Times New =
Roman"=20
  size=3D3> </FONT><FONT face=3Dsans-serif color=3Dblue =
size=3D2><BR>&nbsp; &nbsp;=20
  &nbsp;different voltages ( 1.77V and &nbsp;1.83V),</FONT><FONT=20
  face=3D"Times New Roman" size=3D3> </FONT><FONT face=3Dsans-serif =
color=3Dblue=20
  size=3D2><BR>&nbsp; &nbsp; &nbsp;a difference of 100.00% and 79.26%,=20
  respectively.</FONT><FONT face=3D"Times New Roman" size=3D3> =
<BR></FONT><FONT=20
  face=3Dsans-serif size=3D2><BR>Please tell me the impact of this =
warning in=20
  simulation. I use XTK for the simulation. Eventhough the rise and fall =
VT=20
  curve values range from 0V to 0.38V in the IBIS model, I get 1.04V to =
1.14V=20
  wave form. How is this related with this. I am using Cypress =
"CY7C65640" hub=20
  controller's IBIS model.</FONT><FONT face=3D"Times New Roman" =
size=3D3>=20
  <BR></FONT><FONT face=3Dsans-serif size=3D2><BR>Awaiting your earliest =

  reply.</FONT><FONT face=3D"Times New Roman" size=3D3> <BR></FONT><FONT =

  face=3Dsans-serif size=3D2><BR>Note: One IBIS parser gives the above =
warnings and=20
  another parser gives them as Errors.</FONT><FONT face=3D"Times New =
Roman"=20
  size=3D3> </FONT><FONT face=3Dsans-serif size=3D2><BR>&nbsp; &nbsp; =
&nbsp; &nbsp;I=20
  do not know whether files can be attached with this mail. If it is OK, =
I can=20
  send &nbsp;the IBIS model.</FONT><FONT face=3D"Times New Roman" =
size=3D3>=20
  </FONT><BR><FONT face=3Dsans-serif size=3D2><BR>thanks &amp; =
regards<BR>K.Muthu=20
  Lakshmi (KML)<BR><BR>SCM Microsystems (India) Pvt. Ltd.<BR>email:=20
  [email-masked]<BR>Web: www.scmmicro.com</FONT><FONT=20
  face=3D"Times New Roman" size=3D3> =
</FONT><BR><BR></BLOCKQUOTE></BODY></HTML>

- ------=_NextPart_000_0007_01C361B9.3C85EDC0--

|------------------------------------------------------------------
|For help or to subscribe/unsubscribe, email [email-masked]
|with just the appropriate command message(s) in the body:
|
|  help
|  subscribe   ibis       <optional e-mail address, if different>
|  subscribe   ibis-users <optional e-mail address, if different>
|  unsubscribe ibis       <optional e-mail address, if different>
|  unsubscribe ibis-users <optional e-mail address, if different>
|
|or email a written request to [email-masked].
|
|IBIS reflector archives exist under:
|
|  http://www.eda.org/pub/ibis/email_archive/  Recent
|  http://www.eda.org/pub/ibis/users_archive/  Recent
|  http://www.eda.org/pub/ibis/email/          E-mail since 1993

------------------------------

Date: Thu, 14 Aug 2003 08:36:05 +0200
From: Pascal GILGENKRANTZ <[email-masked]>
Subject: Re: [IBIS-Users] IBIS model Error

Hello Allen,

I ran into the same a few weeks ago. I found the answer in 
the free "Visual IBIS Editor" (From Innoveda) in the help menu
which is very well explained.
  -> Help Menu
  -> Verifying IBIS Models
  -> V/t and V/I Table Data are Mismatched

Available from Mentor Web site : http://www.mentor.com/hyperlynx/visibis.cfm

Pascal Gilgenkrantz
STMicroelectronics

> [email-masked] wrote:
> 
> Hi IBIS experts,
> I have the same problem as Muthu Lakshmi. I don't really understand how the
> parser calculated the DC end points from the IV table... If anyone can
> kindly show me how it works or know where to find the information on the
> internet, it will be greatly appreciated.
> 
> Thanks in advance,
> 
> Allen Chao
>
|------------------------------------------------------------------
|For help or to subscribe/unsubscribe, email [email-masked]
|with just the appropriate command message(s) in the body:
|
|  help
|  subscribe   ibis       <optional e-mail address, if different>
|  subscribe   ibis-users <optional e-mail address, if different>
|  unsubscribe ibis       <optional e-mail address, if different>
|  unsubscribe ibis-users <optional e-mail address, if different>
|
|or email a written request to [email-masked].
|
|IBIS reflector archives exist under:
|
|  http://www.eda.org/pub/ibis/email_archive/  Recent
|  http://www.eda.org/pub/ibis/users_archive/  Recent
|  http://www.eda.org/pub/ibis/email/          E-mail since 1993

------------------------------

Date: Thu, 14 Aug 2003 12:28:56 +0530
From: "Birendra Rana" <[email-masked]>
Subject: RE: [IBIS-Users] IBIS model Error

This is a multi-part message in MIME format.

- ------_=_NextPart_001_01C36231.87B06F10
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	charset="us-ascii"
Content-Transfer-Encoding: quoted-printable

Hi,
=20
Such errors are encountered when the IBIS model is not generated
properly. One reason of getting this kind of error, as per my
experience, is when the ramp tables haven't captured the full waveform.
The ibischk utility takes the 'not fully settled' final value of the
ramp as the stable end value and compares with the IV table DC end point
and flags an error or warning depending on how big is the difference.
Because of this reason I have seen errors/warnings normally flagged for
one end point.
=20
Muthu Lakshmi's error reports however have large difference at the two
end points which means the problem lies else where.=20
=20
Regards,
=20
Birendra

- -----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of Allen Chao
Sent: Thursday, 14 August 2003 2:08 AM
To: [email-masked]; [email-masked];
[email-masked]
Subject: RE: [IBIS-Users] IBIS model Error

Hi IBIS experts,
I have the same problem as Muthu Lakshmi. I don't really understand how
the parser calculated the DC end points from the IV table... If anyone
can kindly show me how it works or know where to find the information on
the internet, it will be greatly appreciated.
=20
Thanks in advance,
=20
Allen Chao=20
=20
=20

- -----Original Message-----
From: [email-masked] [mailto:[email-masked]]On
Behalf Of [email-masked]
Sent: Monday, July 28, 2003 4:10 AM
To: [email-masked]; [email-masked]
Subject: Re: [IBIS-Users] IBIS model Error

Hello Muthu Lakshmi,=20

I think there is something wrong with your IBIS model. The DC end points
calculated from the I-V tables should match the V-T end points (logic
levels). If the error is within 2% you should get a warning, otherwise
an error. The difference you mention is very big.=20

The DC end points are calculated from the I-V tables (therefore you
don't see the end points of the V-T table). The I-V tables are derived
by sweeping a voltage at the output and measuring the resulting current.
By applying a certain load the voltages from the logic high and low
level are calculated from the pull-up and pull-down curve (and of course
they should be near the waveform end point voltages). The V-T data is
used to describe the transition between the logic levels calculated from
the I-V data.=20

I would suggest that you contact Cypress to ask if this model is OK.=20

With kind regards,=20

Ir. Erik van der Ven
Room DB1032
Business Line Networking Infrastructure
Philips Semiconductors BV
Gerstweg 2
6534 AE Nijmegen
The Netherlands
Phone: +31-24-3534334=20

=09

[email-masked]=20

Sent by:=20
[email-masked]=20

07/28/03 05:32 AM=20

       =20
        To:        [email-masked]=20
        cc:        (bcc: Erik van der Ven/NYM/SC/PHILIPS)=20
        Subject:        [IBIS-Users] IBIS model Error=20

        Classification:        =20

Hi All,=20

I need IBIS expert's advice on the following.=20

I get the following warning when checking the IBIS model.=20

Warning - Model bp_usb_hs: The [Rising Waveform]=20
     with [R_fixture]=3D45 Ohms and [V_fixture]=3D0V=20
     has TYP column DC endpoints of  0.00V and  0.38v, but=20
     an equivalent load applied to the model's I-V tables yields=20
     different voltages ( 1.14V and  1.06V),=20
     a difference of 99.99% and 64.28%, respectively.=20

Warning - Model bp_usb_hs: The [Falling Waveform]=20
     with [R_fixture]=3D45 Ohms and [V_fixture]=3D0V=20
     has TYP column DC endpoints of  0.00V and  0.38v, but=20
     an equivalent load applied to the model's I-V tables yields=20
     different voltages ( 1.14V and  1.06V),=20
     a difference of 99.99% and 64.28%, respectively.=20

Warning - Model bp_usb_hs: The [Rising Waveform]=20
     with [R_fixture]=3D45 Ohms and [V_fixture_min]=3D0V=20
     has MIN column DC endpoints of  0.00V and  0.37v, but=20
     an equivalent load applied to the model's I-V tables yields=20
     different voltages ( 1.09V and  0.93V),=20
     a difference of 99.99% and 60.23%, respectively.=20

Warning - Model bp_usb_hs: The [Falling Waveform]=20
     with [R_fixture]=3D45 Ohms and [V_fixture_min]=3D0V=20
     has MIN column DC endpoints of  0.00V and  0.37v, but=20
     an equivalent load applied to the model's I-V tables yields=20
     different voltages ( 1.09V and  0.93V),=20
     a difference of 99.99% and 60.23%, respectively.=20

Warning - Model bp_usb_hs: The [Rising Waveform]=20
     with [R_fixture]=3D45 Ohms and [V_fixture_max]=3D0V=20
     has MAX column DC endpoints of  0.00V and  0.39v, but=20
     an equivalent load applied to the model's I-V tables yields=20
     different voltages ( 1.77V and  1.83V),=20
     a difference of 100.00% and 78.72%, respectively.=20

Warning - Model bp_usb_hs: The [Falling Waveform]=20
     with [R_fixture]=3D45 Ohms and [V_fixture_max]=3D0V=20
     has MAX column DC endpoints of  0.00V and  0.38v, but=20
     an equivalent load applied to the model's I-V tables yields=20
     different voltages ( 1.77V and  1.83V),=20
     a difference of 100.00% and 79.26%, respectively.=20

Please tell me the impact of this warning in simulation. I use XTK for
the simulation. Eventhough the rise and fall VT curve values range from
0V to 0.38V in the IBIS model, I get 1.04V to 1.14V wave form. How is
this related with this. I am using Cypress "CY7C65640" hub controller's
IBIS model.=20

Awaiting your earliest reply.=20

Note: One IBIS parser gives the above warnings and another parser gives
them as Errors.=20
       I do not know whether files can be attached with this mail. If it
is OK, I can send  the IBIS model.=20

thanks & regards
K.Muthu Lakshmi (KML)

SCM Microsystems (India) Pvt. Ltd.
email: [email-masked]
Web: www.scmmicro.com=20

- ------_=_NextPart_001_01C36231.87B06F10
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META HTTP-EQUIV=3D"Content-Type" CONTENT=3D"text/html; =
charset=3Dus-ascii">
<TITLE>Message</TITLE>

<META content=3D"MSHTML 6.00.2713.1100" name=3DGENERATOR></HEAD>
<BODY>
<DIV><FONT color=3D#008000>
<DIV><SPAN class=3D424424705-14082003><FONT face=3D"Comic Sans MS" =
color=3D#000000=20
size=3D2>Hi,</FONT></SPAN></DIV>
<DIV><SPAN class=3D424424705-14082003><FONT face=3D"Comic Sans MS" =
color=3D#000000=20
size=3D2></FONT></SPAN>&nbsp;</DIV>
<DIV><SPAN class=3D424424705-14082003><FONT face=3D"Comic Sans MS" =
color=3D#000000=20
size=3D2>Such errors&nbsp;are encountered when the IBIS model is not =
generated=20
properly.&nbsp;One reason of getting this kind of error, as per my =
experience,=20
is when the ramp tables haven't captured the full waveform.&nbsp;The =
ibischk=20
utility takes the&nbsp;'not fully settled' final value of the ramp as =
the stable=20
end value and compares with the IV table DC end point and flags an error =
or=20
warning&nbsp;depending on how big is the difference.&nbsp;Because of =
this reason=20
I have seen&nbsp;errors/warnings normally&nbsp;flagged for one end=20
point.</FONT></SPAN></DIV>
<DIV><SPAN class=3D424424705-14082003><FONT face=3D"Comic Sans MS" =
color=3D#000000=20
size=3D2></FONT></SPAN>&nbsp;</DIV>
<DIV><SPAN class=3D424424705-14082003><FONT face=3D"Comic Sans MS" =
color=3D#000000=20
size=3D2>Muthu&nbsp;Lakshmi's error reports however&nbsp;have large =
difference at=20
the two end points&nbsp;which means the problem lies else where.=20
</FONT></SPAN></DIV>
<DIV><SPAN class=3D424424705-14082003><FONT face=3D"Comic Sans MS" =
color=3D#000000=20
size=3D2></FONT></SPAN>&nbsp;</DIV>
<DIV><SPAN class=3D424424705-14082003><FONT face=3D"Comic Sans MS" =
color=3D#000000=20
size=3D2>Regards,</FONT></SPAN></DIV>
<DIV><SPAN class=3D424424705-14082003><FONT face=3D"Comic Sans MS" =
color=3D#000000=20
size=3D2></FONT></SPAN>&nbsp;</DIV>
<DIV><SPAN class=3D424424705-14082003><FONT face=3D"Comic Sans MS" =
color=3D#000000=20
size=3D2>Birendra</FONT></SPAN></DIV></FONT></DIV>
<BLOCKQUOTE dir=3Dltr style=3D"MARGIN-RIGHT: 0px">
  <DIV></DIV>
  <DIV class=3DOutlookMessageHeader lang=3Den-us dir=3Dltr =
align=3Dleft><FONT=20
  face=3DTahoma size=3D2>-----Original Message-----<BR><B>From:</B>=20
  [email-masked] [mailto:[email-masked]] <B>On =
Behalf Of=20
  </B>Allen Chao<BR><B>Sent:</B> Thursday, 14 August 2003 2:08 =
AM<BR><B>To:</B>=20
  [email-masked]; [email-masked];=20
  [email-masked]<BR><B>Subject:</B> RE: [IBIS-Users] IBIS model=20
  Error<BR><BR></FONT></DIV>
  <DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN =
class=3D129252920-13082003>Hi=20
  IBIS experts,</SPAN></FONT></DIV>
  <DIV><FONT color=3D#0000ff size=3D2><SPAN =
class=3D129252920-13082003><FONT=20
  face=3DArial>I have the same problem as&nbsp;Muthu Lakshmi. I don't =
really=20
  understand how the parser calculated the&nbsp;DC end points from the =
IV=20
  table... If anyone can kindly show me how it works or know where to =
find the=20
  information on the internet,&nbsp;it will be greatly=20
  appreciated.</FONT></SPAN></FONT></DIV>
  <DIV><FONT color=3D#0000ff size=3D2><SPAN=20
  class=3D129252920-13082003></SPAN></FONT>&nbsp;</DIV>
  <DIV><FONT color=3D#0000ff size=3D2><SPAN =
class=3D129252920-13082003><FONT=20
  face=3DArial>Thanks&nbsp;in advance,</FONT></SPAN></FONT></DIV>
  <DIV><FONT color=3D#0000ff size=3D2><SPAN=20
  class=3D129252920-13082003></SPAN></FONT>&nbsp;</DIV>
  <DIV><FONT color=3D#0000ff size=3D2><SPAN =
class=3D129252920-13082003><FONT=20
  face=3DArial>Allen Chao</FONT>&nbsp;</SPAN></FONT></DIV>
  <DIV><FONT color=3D#0000ff size=3D2><SPAN =
class=3D129252920-13082003><FONT=20
  face=3D"Lucida Sans Unicode"></FONT></SPAN></FONT>&nbsp;</DIV>
  <DIV><FONT face=3D"Lucida Sans Unicode" color=3D#0000ff size=3D2><SPAN =

  class=3D129252920-13082003></SPAN></FONT>&nbsp;</DIV>
  <BLOCKQUOTE>
    <DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
    size=3D2>-----Original Message-----<BR><B>From:</B> =
[email-masked]=20
    [mailto:[email-masked]]<B>On Behalf Of=20
    </B>[email-masked]<BR><B>Sent:</B> Monday, July 28, =
2003 4:10=20
    AM<BR><B>To:</B> [email-masked];=20
    [email-masked]<BR><B>Subject:</B> Re: [IBIS-Users] IBIS model=20
    Error<BR><BR></FONT></DIV><BR><FONT face=3Dsans-serif size=3D2>Hello =
Muthu=20
    Lakshmi,</FONT> <BR><BR><FONT face=3Dsans-serif size=3D2>I think =
there is=20
    something wrong with your IBIS model. The DC end points calculated =
from the=20
    I-V tables should match the V-T end points (logic levels). If the =
error is=20
    within 2% you should get a warning, otherwise an error. The =
difference you=20
    mention is very big.</FONT> <BR><BR><FONT face=3Dsans-serif =
size=3D2>The DC end=20
    points are calculated from the I-V tables (therefore you don't see =
the end=20
    points of the V-T table). The I-V tables are derived by sweeping a =
voltage=20
    at the output and measuring the resulting current. By applying a =
certain=20
    load the voltages from the logic high and low level are calculated =
from the=20
    pull-up and pull-down curve (and of course they should be near the =
waveform=20
    end point voltages). The V-T data is used to describe the transition =
between=20
    the logic levels calculated from the I-V data.</FONT> <BR><BR><FONT=20
    face=3Dsans-serif size=3D2>I would suggest that you contact Cypress =
to ask if=20
    this model is OK.</FONT> <BR><BR><BR><FONT face=3Dsans-serif =
size=3D2>With kind=20
    regards,</FONT> <BR><BR><FONT face=3Dsans-serif size=3D2><BR>Ir. =
Erik van der=20
    Ven<BR>Room DB1032<BR>Business Line Networking =
Infrastructure<BR>Philips=20
    Semiconductors BV<BR>Gerstweg 2<BR>6534 AE Nijmegen<BR>The=20
    Netherlands<BR>Phone: +31-24-3534334</FONT> <BR><BR><BR>
    <TABLE width=3D"100%">
      <TBODY>
      <TR vAlign=3Dtop>
        <TD>
        <TD><BR><BR><BR><BR><BR><FONT face=3Dsans-serif=20
          size=3D1><B>[email-masked]</B></FONT>=20
          <P><FONT face=3Dsans-serif size=3D1>Sent by: </FONT><BR><FONT=20
          face=3Dsans-serif size=3D1>[email-masked]</FONT>=20
          <P><FONT face=3Dsans-serif size=3D1>07/28/03 05:32 AM</FONT> =
<BR></P>
        <TD><FONT face=3DArial size=3D1>&nbsp; &nbsp; &nbsp; &nbsp;=20
          </FONT><BR><FONT face=3Dsans-serif size=3D1>&nbsp; &nbsp; =
&nbsp; &nbsp;=20
          To: &nbsp; &nbsp; &nbsp; &nbsp;[email-masked]</FONT> =
<BR><FONT=20
          face=3Dsans-serif size=3D1>&nbsp; &nbsp; &nbsp; &nbsp; cc: =
&nbsp; &nbsp;=20
          &nbsp; &nbsp;(bcc: Erik van der Ven/NYM/SC/PHILIPS)</FONT> =
<BR><FONT=20
          face=3Dsans-serif size=3D1>&nbsp; &nbsp; &nbsp; &nbsp; =
Subject: &nbsp;=20
          &nbsp; &nbsp; &nbsp;[IBIS-Users] IBIS model Error</FONT>=20
          <P><FONT face=3Dsans-serif size=3D1>&nbsp; &nbsp; &nbsp; =
&nbsp;=20
          Classification: &nbsp; &nbsp; &nbsp; &nbsp;</FONT>=20
      <BR></P></TD></TR></TBODY></TABLE><BR><BR><BR><FONT =
face=3Dsans-serif=20
    size=3D2><BR>Hi All,</FONT><FONT face=3D"Times New Roman" size=3D3>=20
    <BR></FONT><FONT face=3Dsans-serif size=3D2><BR>I need IBIS expert's =
advice on=20
    the following.</FONT><FONT face=3D"Times New Roman" size=3D3> =
<BR></FONT><FONT=20
    face=3Dsans-serif size=3D2><BR>I get the following warning when =
checking the=20
    IBIS model. </FONT><FONT face=3D"Times New Roman" =
size=3D3><BR></FONT><FONT=20
    face=3Dsans-serif color=3Dblue size=3D2><BR>Warning - Model =
bp_usb_hs: The [Rising=20
    Waveform] <BR>&nbsp; &nbsp; &nbsp;with [R_fixture]=3D45 Ohms and=20
    [V_fixture]=3D0V</FONT><FONT face=3D"Times New Roman" size=3D3> =
</FONT><FONT=20
    face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; &nbsp;has =
TYP column DC=20
    endpoints of &nbsp;0.00V and &nbsp;0.38v, but</FONT><FONT=20
    face=3D"Times New Roman" size=3D3> </FONT><FONT face=3Dsans-serif =
color=3Dblue=20
    size=3D2><BR>&nbsp; &nbsp; &nbsp;an equivalent load applied to the =
model's I-V=20
    tables yields</FONT><FONT face=3D"Times New Roman" size=3D3> =
</FONT><FONT=20
    face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; =
&nbsp;different voltages=20
    ( 1.14V and &nbsp;1.06V),</FONT><FONT face=3D"Times New Roman" =
size=3D3>=20
    </FONT><FONT face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; =
&nbsp; &nbsp;a=20
    difference of 99.99% and 64.28%, respectively.</FONT><FONT=20
    face=3D"Times New Roman" size=3D3> <BR></FONT><FONT =
face=3Dsans-serif color=3Dblue=20
    size=3D2><BR>Warning - Model bp_usb_hs: The [Falling Waveform] =
<BR>&nbsp;=20
    &nbsp; &nbsp;with [R_fixture]=3D45 Ohms and =
[V_fixture]=3D0V</FONT><FONT=20
    face=3D"Times New Roman" size=3D3> </FONT><FONT face=3Dsans-serif =
color=3Dblue=20
    size=3D2><BR>&nbsp; &nbsp; &nbsp;has TYP column DC endpoints of =
&nbsp;0.00V=20
    and &nbsp;0.38v, but</FONT><FONT face=3D"Times New Roman" size=3D3> =
</FONT><FONT=20
    face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; &nbsp;an =
equivalent load=20
    applied to the model's I-V tables yields</FONT><FONT face=3D"Times =
New Roman"=20
    size=3D3> </FONT><FONT face=3Dsans-serif color=3Dblue =
size=3D2><BR>&nbsp; &nbsp;=20
    &nbsp;different voltages ( 1.14V and &nbsp;1.06V),</FONT><FONT=20
    face=3D"Times New Roman" size=3D3> </FONT><FONT face=3Dsans-serif =
color=3Dblue=20
    size=3D2><BR>&nbsp; &nbsp; &nbsp;a difference of 99.99% and 64.28%,=20
    respectively.</FONT><FONT face=3D"Times New Roman" size=3D3> =
<BR></FONT><FONT=20
    face=3Dsans-serif color=3Dblue size=3D2><BR>Warning - Model =
bp_usb_hs: The [Rising=20
    Waveform] <BR>&nbsp; &nbsp; &nbsp;with [R_fixture]=3D45 Ohms and=20
    [V_fixture_min]=3D0V</FONT><FONT face=3D"Times New Roman" size=3D3> =
</FONT><FONT=20
    face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; &nbsp;has =
MIN column DC=20
    endpoints of &nbsp;0.00V and &nbsp;0.37v, but</FONT><FONT=20
    face=3D"Times New Roman" size=3D3> </FONT><FONT face=3Dsans-serif =
color=3Dblue=20
    size=3D2><BR>&nbsp; &nbsp; &nbsp;an equivalent load applied to the =
model's I-V=20
    tables yields</FONT><FONT face=3D"Times New Roman" size=3D3> =
</FONT><FONT=20
    face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; =
&nbsp;different voltages=20
    ( 1.09V and &nbsp;0.93V),</FONT><FONT face=3D"Times New Roman" =
size=3D3>=20
    </FONT><FONT face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; =
&nbsp; &nbsp;a=20
    difference of 99.99% and 60.23%, respectively.</FONT><FONT=20
    face=3D"Times New Roman" size=3D3> <BR></FONT><FONT =
face=3Dsans-serif color=3Dblue=20
    size=3D2><BR>Warning - Model bp_usb_hs: The [Falling Waveform] =
<BR>&nbsp;=20
    &nbsp; &nbsp;with [R_fixture]=3D45 Ohms and =
[V_fixture_min]=3D0V</FONT><FONT=20
    face=3D"Times New Roman" size=3D3> </FONT><FONT face=3Dsans-serif =
color=3Dblue=20
    size=3D2><BR>&nbsp; &nbsp; &nbsp;has MIN column DC endpoints of =
&nbsp;0.00V=20
    and &nbsp;0.37v, but</FONT><FONT face=3D"Times New Roman" size=3D3> =
</FONT><FONT=20
    face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; &nbsp;an =
equivalent load=20
    applied to the model's I-V tables yields</FONT><FONT face=3D"Times =
New Roman"=20
    size=3D3> </FONT><FONT face=3Dsans-serif color=3Dblue =
size=3D2><BR>&nbsp; &nbsp;=20
    &nbsp;different voltages ( 1.09V and &nbsp;0.93V),</FONT><FONT=20
    face=3D"Times New Roman" size=3D3> </FONT><FONT face=3Dsans-serif =
color=3Dblue=20
    size=3D2><BR>&nbsp; &nbsp; &nbsp;a difference of 99.99% and 60.23%,=20
    respectively.</FONT><FONT face=3D"Times New Roman" size=3D3> =
<BR></FONT><FONT=20
    face=3Dsans-serif color=3Dblue size=3D2><BR>Warning - Model =
bp_usb_hs: The [Rising=20
    Waveform] <BR>&nbsp; &nbsp; &nbsp;with [R_fixture]=3D45 Ohms and=20
    [V_fixture_max]=3D0V</FONT><FONT face=3D"Times New Roman" size=3D3> =
</FONT><FONT=20
    face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; &nbsp;has =
MAX column DC=20
    endpoints of &nbsp;0.00V and &nbsp;0.39v, but</FONT><FONT=20
    face=3D"Times New Roman" size=3D3> </FONT><FONT face=3Dsans-serif =
color=3Dblue=20
    size=3D2><BR>&nbsp; &nbsp; &nbsp;an equivalent load applied to the =
model's I-V=20
    tables yields</FONT><FONT face=3D"Times New Roman" size=3D3> =
</FONT><FONT=20
    face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; =
&nbsp;different voltages=20
    ( 1.77V and &nbsp;1.83V),</FONT><FONT face=3D"Times New Roman" =
size=3D3>=20
    </FONT><FONT face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; =
&nbsp; &nbsp;a=20
    difference of 100.00% and 78.72%, respectively.</FONT><FONT=20
    face=3D"Times New Roman" size=3D3> <BR></FONT><FONT =
face=3Dsans-serif color=3Dblue=20
    size=3D2><BR>Warning - Model bp_usb_hs: The [Falling Waveform] =
<BR>&nbsp;=20
    &nbsp; &nbsp;with [R_fixture]=3D45 Ohms and =
[V_fixture_max]=3D0V</FONT><FONT=20
    face=3D"Times New Roman" size=3D3> </FONT><FONT face=3Dsans-serif =
color=3Dblue=20
    size=3D2><BR>&nbsp; &nbsp; &nbsp;has MAX column DC endpoints of =
&nbsp;0.00V=20
    and &nbsp;0.38v, but</FONT><FONT face=3D"Times New Roman" size=3D3> =
</FONT><FONT=20
    face=3Dsans-serif color=3Dblue size=3D2><BR>&nbsp; &nbsp; &nbsp;an =
equivalent load=20
    applied to the model's I-V tables yields</FONT><FONT face=3D"Times =
New Roman"=20
    size=3D3> </FONT><FONT face=3Dsans-serif color=3Dblue =
size=3D2><BR>&nbsp; &nbsp;=20
    &nbsp;different voltages ( 1.77V and &nbsp;1.83V),</FONT><FONT=20
    face=3D"Times New Roman" size=3D3> </FONT><FONT face=3Dsans-serif =
color=3Dblue=20
    size=3D2><BR>&nbsp; &nbsp; &nbsp;a difference of 100.00% and 79.26%, =

    respectively.</FONT><FONT face=3D"Times New Roman" size=3D3> =
<BR></FONT><FONT=20
    face=3Dsans-serif size=3D2><BR>Please tell me the impact of this =
warning in=20
    simulation. I use XTK for the simulation. Eventhough the rise and =
fall VT=20
    curve values range from 0V to 0.38V in the IBIS model, I get 1.04V =
to 1.14V=20
    wave form. How is this related with this. I am using Cypress =
"CY7C65640" hub=20
    controller's IBIS model.</FONT><FONT face=3D"Times New Roman" =
size=3D3>=20
    <BR></FONT><FONT face=3Dsans-serif size=3D2><BR>Awaiting your =
earliest=20
    reply.</FONT><FONT face=3D"Times New Roman" size=3D3> =
<BR></FONT><FONT=20
    face=3Dsans-serif size=3D2><BR>Note: One IBIS parser gives the above =
warnings=20
    and another parser gives them as Errors.</FONT><FONT face=3D"Times =
New Roman"=20
    size=3D3> </FONT><FONT face=3Dsans-serif size=3D2><BR>&nbsp; &nbsp; =
&nbsp; &nbsp;I=20
    do not know whether files can be attached with this mail. If it is =
OK, I can=20
    send &nbsp;the IBIS model.</FONT><FONT face=3D"Times New Roman" =
size=3D3>=20
    </FONT><BR><FONT face=3Dsans-serif size=3D2><BR>thanks &amp; =
regards<BR>K.Muthu=20
    Lakshmi (KML)<BR><BR>SCM Microsystems (India) Pvt. Ltd.<BR>email:=20
    [email-masked]<BR>Web: www.scmmicro.com</FONT><FONT=20
    face=3D"Times New Roman" size=3D3>=20
</FONT><BR><BR></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>

- ------_=_NextPart_001_01C36231.87B06F10--
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------------------------------

Date: Thu, 14 Aug 2003 08:27:15 -0600
From: [email-masked]
Subject: [IBIS-Users] [IBIS] Open forum minutes (08/08/03)

DATE: 8/14/03

SUBJECT: August 8, 2003 EIA IBIS Open Forum Meeting Minutes

VOTING MEMBERS AND 2003 PARTICIPANTS LIST:
Ansoft Corporation             (Eric Bracken)
Apple Computer                 Kim Helliwell
Applied Simulation Technology  Fred Balistreri
Cadence Design                 Lynne Green*, Lance Wang
Cisco Systems                  Syed Huq, Michael LaBonte,
                               Val Mandruson, Hung Pham,
                               Todd Westerhoff
Fairchild Semiconductor        (Graham Connolly)
Hitachi ULSI Systems           Kazuyoshi Shoji
Intel Corporation              Stephen Peters, Michael Mirmak*,
                               Arpad Muranyi*, Eric Magnusson
LSI Logic                      Frank Gasparik*
Matsushita (Panasonic)         Atsuji Ito
Mentor Graphics                [Bob Ross], Ian Dodd, Guy de Burgh*,
                               John Angulo*, Mike Donnelly, Weston Beal 
Micron Technology              Randy Wolff*
Molex Incorporated             Gus Panella
Motorola                       (Rick Kingen)
National Semiconductor         [Milt Schwartz], [Tim Coyle]
NEC Electric Corporation       (Itsuki Yamada)
Philips Semiconductor          (D.C. Sessions), Stephanie Goedecke
Siemens (& Automotive) AG      Eckhard Lenski, Michael Kindij, 
                               Burkhard Muller, Katja Koller, 
                               Andre Goerisch, Manfred Maurer, 
                               Bernard Unger, Amir Motamedi, 
                               Hartmut Ibowski, Gerald Bannert
Signal Integrity Software      Bob Haller, Barry Katz, Doug Burns
Sigrity                        [Raj Raghuram]
Synopsys                       Warren Wong, Edmund Cheng
Texas Instruments              Thomas Fisher
Teraspeed                      Scott McMorrow, Tom Dagostino,
                               Kevin Simpson, Bob Ross*
Time Domain Analysis Systems   Dima Smolyansky, Steve Corey
Zuken (& Incases)              Michael Schaeder, Ralf Bruening

OTHER PARTICIPANTS IN 2003:
Agilent Technologies           Herbert Lage
Brocade                        Frank Yuan, Yongrue Yu
Conexant                       Gary Felker
EADS CCR                       Alix de la Villeguerin
EFM                            Ekkehard Miersch
EMC Corporation                Brian Arsenault, John Fernandez,
                               Simba Julian
Fraunhofer IZM                 Ege Engin
Fujitsu                        Tadashi Arai
GEIA                           (Chris Denham)
Huawei Technologies            (Jiang Xiang Zhong)
Independent                    Kelly Green, Luca Giacotto
Infineon Tech AG               Christian Sporrer
Marvell Semiconductor          Itzik Peleg
NetLogic Microsystems          Eric Hsu
North East Systems Associates  Edward Sayre 
North Carolina State Univ.     Ambrish Varma* 
Plexus                         Joseph Socha
Politechnico de Torino         Igor Stievano
Qlogic                         Larry Barnes
Sintecs BV                     Hans Klos, Bob te Nijenhuis
SiQual                         (Rob Hinz)
Sun Microsystems               Tim Coyle*
Via Technologies               (Weber Chuang)
Xilinx                         Susan Wu

In the list above, attendees at the meeting are indicated by *.  Principal
members or other active members who have not attended are in parentheses. 
Participants who no longer are in the organization are in square brackets.

Upcoming Meetings:  The bridge numbers for future IBIS teleconferences are 
as follows:

       Date           Bridge Number    Reservation #    Passcode
  August 22, 2003     1-916-356-2663        4           696-0504

All meetings are 8:00 AM to 9:55 AM Pacific Time.  Meeting agendas are
typically distributed seven days before each Open Forum.  Minutes are 
typically distributed within seven days of the corresponding meeting.
When calling into the meeting, provide the reservation number and 
passcode at the automated prompts.  If asked by an operator, please
request to join the IBIS Open Forum hosted by Michael Mirmak.

NOTE: "AR" = Action Required.

- -------------------------------- MINUTES -----------------------------------
INTRODUCTIONS AND MEETING QUORUM
Ambrish Varma of North Carolina State University introduced himself.  He
is a Ph. D. candidate currently involved in research related to IBIS and
is developing the S2IBIS3 IBIS model generation software.

CALL FOR PATENTS
Michael Mirmak called for any patents or pending patents related to the
IBIS Version 4.0, 4.1 or ICM specifications. No companies declared a patent.

MEMBERSHIP UPDATE AND TREASURER'S REPORT
Michael Mirmak reported that membership remains at 25 organizations.  A
minor problem with one company's GEIA invoice has been resolved and
all payments are expected to be complete shortly.

REVIEW OF MINUTES AND AR'S
The July 18 meeting minutes were approved without objection.

MISCELLANY/ANNOUNCEMENTS
No new announcements.

PRESS AND WEB PAGE UPDATES
Bob Ross reported that Syed has completed a first revision of the 
on-line IBIS roster.  Most member companies and organizations have
provided updated information.

NEW MODELS AVAILABLE, LIBRARY UPDATE
No update.

OPENS FOR NEW ISSUES
Tim Coyle raised some concerns regarding the IBIS web pages.  While the 
information there is useful, the most recent article is from 2000 and 
none of the information is searchable.  More current technical and 
application notes from specific companies are not available.  Tim 
proposed more active cross-referencing of papers and other company-
specific links, if not creating a new domain for the IBIS community.  Bob 
Ross noted that the EIA controls the eigroup.org web site and that access 
and updating is limited for security reasons.  Michael requested that Tim 
work with webmaster Syed Huq on either updating the current site per Tim's
suggestions, or creating a new web domain.

INTERNATIONAL/EXTERNAL PROGRESS
- - IEC 62014-3 (ICEM) Integrated Circuit Electromagnetic Model Proposal
  (formerly, IEC 93/67/NP IBIS and EMC Simulation)
  No update.
- - JEDEC Activity Report. 
  No update.

DATE/PCB EAST SUMMIT DISCUSSION
Lynne Green reported that a draft call for papers has been prepared and 
is ready for distribution in mid-August.  Michael Mirmak described his 
conversation with Ed Sayre of NESA and reported that NESA has no 
objection to hosting a summit at NESA on Tuesday, October 21.  
Confirmation of the details has not yet been received, however.  Michael
accepted the AR to confirm room and refreshment/lunch arrangements with
Kathy Breda of NESA.

DESIGNCON SUMMIT DISCUSSION
Michael Mirmak reported that he spoke with Brock Silvey of DesignCon
2004.  The contract and logistical arrangements for an IBIS Summit
at DesignCon 2004 are nearly complete, though some issues regarding
refreshments still remain to be resolved.  A draft co-sponsorship
agreement has been received and is being reviewed by the Open Forum
officers.  The summit is tentatively scheduled for Monday, Feb. 2, 2004.

IBIS VERSION 4.0 PARSER FUNDING AND STATUS
Michael Mirmak reported that all invoices for the 4.0 parser have been
distributed and confirmed received.  Payment from one remaining organization
is expected shortly.

A beta version of IBISCHK4 has been compiled and is available for download:

http://www.vhdl.org/pub/ibis/ibischk4_beta

IBIS QUALITY COMMITTEE
Bob Ross reported that meetings continue every two weeks.

IBIS MODEL REVIEW COMMITTEE
Lynne Green reported that no new models have been received by the 
committee since the last Open Forum meeting.

NEW ADMINISTRATIVE ISSUES
No new issues.

S2IBIS3
Ambrish Varma noted that he has created a publicly-available website
for the S2IBIS3 project:

http://www.ece.ncsu.edu/erl/ibis/s2ibis3/s2ibis3.htm

Feedback on the current beta version is appreciated and encouraged.
Ambrish also mentioned that he and Bob Ross have been recently working on 
debugging support of the [Series MOSFET] keyword.  The current version of 
the software supports, under Java, all the S2IBIS2 version 2.1 commands 
except [Summarize].  Previously noted issues with print resolution have 
been addressed and more comprehensive version control will be implemented.

BIRD74.5 - EMI Parameters
Guy de Burgh introduced the updated text of BIRD74.5.  He described
six minor changes suggested to him via e-mail since the last review; 
these include:

- - explicitly stating that the "Domain" and "Cpd" subparameters and 
  arguments are not required and may be omitted

- - changing the phrase "The keyword takes one argument" under 
  "Heatsink_cap" to "The sub-parameter takes one argument"

- - requiring the "domain_name" column for [Pin EMI] to help the 
  parsing of the columns, even if the data is NA

- - using the word "maximum" in place of "dominant" for the 
  description of the clock division sub-parameter  

- - clarifying that [Begin EMI Model] and [End EMI Model] must occur 
  after the [Model] keyword with which they are associated; similar
  rules would apply to EMI keywords related to [Component]

- - a global change of "sub-parameter" to "subparameter"

Guy accepted all suggested changes and noted that these do not affect the 
technical content of the BIRD.  Some discussion arose regarding the 
version in which this BIRD is to be included.  Bob Ross suggested that the
BIRD become part of the next major release, likely to be IBIS 5.0.

The BIRD was approved as amended by a vote of four in favor with
one opposed.  The text will be posted with changes as BIRD74.6.

BIRD82.1 - Clarification of Clamp Tables
Bob Ross noted that BIRD82.1 has been posted and distributed for
consideration at the next IBIS Open Forum meeting.

IBIS VERSION 4.1 DISCUSSION
A discussion was held regarding C_comp and [Ramp], and their relationship
to the multi-lingual extensions proposed as part of IBIS 4.1.  Lynne Green
and John Angulo noted that several tools use the [Ramp] keyword as an 
approximate slew rate, for efficient automated prioritization of SI 
problems.  This data is also useful for setting initial simulation engine 
timesteps and therefore improve simulation efficiency.  C_comp was 
considered less strongly needed as a required parameter.  At present, both 
keywords are considered optional when multi-lingual extensions are 
correctly used in an IBIS file.   Arpad Muranyi observed that [Ramp] data,
being single-ended, may not apply for differential waveforms or may imply 
behaviors outside of the normal operation of the device being modeled.

John Angulo proposed that a BIRD be written to include a new keyword,
[Slew Time] or similar, which would enable tools to set initial timesteps
without requiring the [Ramp] keyword.  Open issues include whether this
is a subparameter under the [External Model] and/or [External Circuit]
keywords and whether both [Ramp] and [Slew Time] may exist in the same
model.  John will provide draft BIRD language at a future Open Forum 
meeting.

A draft version of IBIS version 4.1 is available on the web.  Both an 
ASCII text and an Adobe PDF version are available at:

  http://www.vhdl.org/pub/ibis/wip/

IBIS ICM SPECIFICATION REVIEW
Michael Mirmak reintroduced the ICM specification and called for comment.
He mentioned that, with most comments and feedback noted, a vote on
approval will be scheduled for Sept. 12.  

IBISCHK4 & BUG TRACKING STATUS
Bob Ross reminded the Open Forum that a beta version of IBISCHK4
is available at:

http://www.vhdl.org/pub/ibis/ibischk4_beta

Bob also reported that all BUGS except 68, 71, 73, 75 and 76 have been 
addressed and fixed in the beta IBISCHK4 parser code.  These are now
listed as "Closed" on the IBIS web site.  BUG80, which has not been
classified, retains its 3.2 behavior in the beta code.

John Angulo noted that he has compared the Windows output running the 
test cases sent by Atul Agarwal against Atul's reference outputs, and found
only minor differences.  Further work will be completed separately by Bob,
John, and Michael Mirmak.

BUG80 - [Model Selector] and [Diff Pin] Ordering
Classification of BUG80 was postponed until the next Open Forum meeting.

NEXT MEETINGS:
By acclamation, the next teleconference has been scheduled for August 22,
one week earlier than usual, to accommodate the upcoming US holiday.
The meeting will be held from 8:00 AM to 10:00 AM Pacific Daylight Time.  

============================================================================
                               NOTES

IBIS CHAIR: Michael Mirmak (916) 356-4261, Fax: (916) 377-1046
            [email-masked]
            Senior Analog Engineer, Intel Corporation
            M/S FM6-45
            1900 Prairie City Rd.
            Folsom, CA  95630

VICE CHAIR: Lynne Green (425) 788-0412, Fax (425) 451-1871
            [email-masked]
            Senior Modeling Engineer, Cadence Design Systems
            320 120th Ave NE, Suite B-103, Bellevue, WA 98005-3016

SECRETARY:  Randy Wolff (208) 363-1764, Fax: (208) 368-3475
            [email-masked]
            Simulation Engineer, Micron Technology, Inc.
            8000 S. Federal Way
            Mail Stop: 1-711
            Boise, ID 83707-0006
        
LIBRARIAN:  Roy Leventhal (847) 590-9398
            [email-masked]
            Consultant, Leventhal Design and Communications
            1924 North Burke Drive
            Arlington Heights, Illinois 60004

WEBMASTER:  Syed Huq (408) 525-3399, Fax: (408) 526-5504
            [email-masked]
            Manager, Hardware Engineering, Cisco Systems
            170 West Tasman Drive
            San Jose, CA 95134-1706

POSTMASTER: John Angulo (425) 497-5077, Fax: (425) 881-1008
            [email-masked]
            Development Engineer, Mentor Graphics
            14715 N.E. 95th Street, Suite 200
            Redmond, WA 98052

This meeting was conducted in accordance with the EIA Legal Guides and EIA 
Manual of Organization and Procedure.

The following e-mail addresses are used:

  [email-masked]
      In the body, for the IBIS Open Forum Reflector:
      subscribe ibis <your e-mail address>

      In the body, for the IBIS Users' Group Reflector:
      subscribe ibis-users <your e-mail address>

      Help and other commands:
      help

  [email-masked]
      To join, change, or drop from either the IBIS Open Forum Reflector
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  [email-masked]
      To obtain general information about IBIS, to ask specific questions
      for individual response, and to inquire about joining the EIA-IBIS
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  [email-masked]
      To send a message to the general IBIS Open Forum Reflector.  This
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  [email-masked]
      To send a message to the IBIS Users' Group Reflector.  This is
      used mostly for IBIS clarification, current modeling issues, and
      general user concerns.  Job posting information is not permitted.

  [email-masked]
      To report ibischk2/3 parser bugs.  The Bug Report Form Resides on
      eda.org in /pub/ibis/bugs/ibischk/bugform.txt along with reported
      bugs.

      To report s2ibis, s2ibis2 and s2iplt bugs, use the Bug Report Forms
      which reside under eda.org in /pub/ibis/bugs/s2ibis/bugs2i.txt,
      /pub/ibis/bugs/s2ibis2/bugs2i2.txt, and
      /pub/ibis/bugs/s2iplt/bugsplt.txt respectively.

Information on IBIS technical contents, IBIS participants, and actual IBIS 
models are available on the IBIS Home page found by selecting the Electronic 
Information Group under:

  http://www.eigroup.org/ibis/ibis.htm

Check the pub/ibis directory on eda.org for more information on previous 
discussions and results.  Logins using anonymous FTP are accepted.
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|
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|  http://www.eda.org/pub/ibis/users_archive/  Recent
|  http://www.eda.org/pub/ibis/email/          E-mail since 1993

------------------------------

Date: Thu, 14 Aug 2003 15:50:37 -0400
From: "Allen Chao" <[email-masked]>
Subject: [IBIS-Users]DC Sweep for the pullup IV curve

Hi IBIS experts,
I have a question concerning the sweep. I have a 3.3V power supply for my
device. However, the logic high voltage is 0.4V and logic low is 0V for my
one of my outputs. Do I do the DC Sweep at the output from -3.3V to 6.6V
or -0.4V to 0.8V?

Thanks a lot for the help,

Allen Chao

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|with just the appropriate command message(s) in the body:
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|  unsubscribe ibis       <optional e-mail address, if different>
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------------------------------

Date: Thu, 14 Aug 2003 16:06:36 -0700
From: "Muranyi, Arpad" <[email-masked]>
Subject: RE: [IBIS-Users]DC Sweep for the pullup IV curve

Allen,

Strictly speaking the spec says the following:

| The stated voltage ranges for I-V tables cover the most common, single
| supply cases.  When multiple supplies are specified, the voltages shall
| extend similarly to values that handle practical extremes in reflected wave
| simulations.
|  
...
| 2) Voltage Ranges:
|    Points for each table must span the voltages listed below:
|
|       Table                   Low Voltage             High Voltage
|       -----------             -----------             ------------
|       [Pulldown]              GND - POWER             POWER + POWER
|       [Pullup]                GND - POWER             POWER + POWER
|       [GND Clamp]             GND - POWER             GND + POWER
|       [POWER Clamp]           POWER                   POWER + POWER
|       [Series Current]        GND - POWER             GND + POWER
|       [Series MOSFET]         GND                     GND + POWER
|
|    As described in the [Pulldown Reference] keyword section, the I-V tables
|    of the [Pullup] and the [POWER Clamp] structures are 'Vcc relative',
|    using the equation:  Vtable = Vcc - Voutput.
|
|    For example, a model with a 5 V power supply voltage should be
|    characterized between (0 - 5) = -5 V and (5 + 5) = 10 V; and a model with
|    a 3.3 V power supply should be characterized between (0 - 3.3) = -3.3 V
|    and (3.3 + 3.3) = 6.6 V for the [Pulldown] table.
|
|    When tabulating output data for ECL type models, the voltage points must
|    span the range of Vcc to Vcc - 2.2 V.  This range applies to both the
|    [Pullup] and [Pulldown] tables.  Note that this range applies ONLY when
|    characterizing an ECL output.
|
|    These voltage ranges must be spanned by the IBIS data.  Data derived from
|    lab measurements may not be able to span these ranges as such and so may
|    need to be extrapolated to cover the full range.  This data must not be
|    left for the simulator to provide.

So according to the spec you would need to do -3.3 to 6.6 V.  However,
this was written in the days when most buffers were switching rail to
rail, and most transmission lines were unterminated having a full reflection.
The spec wanted to make sure that the IV curves would cover the voltage
range even if the waveforms double due to reflections.

Lately, the picture has changed, and we have more low voltage swing signals
and parallel terminated buses.  As a consequence buffers do not necessarily
switch rail to rail, and reflections are much smaller.  Even if we followed
the logic of full reflections, your model should be sufficient if it covered
- -0.4 to 0.8 V.  This would be officially not according to the spec, but
as far as I remember, the parser doesn't issue an error message, so you
should be OK.

I am dealing with similar situations in other cases too, and I am
actually considering writing a BIRD on this subject to clarify/change
the spec.

Arpad Muranyi
Intel Corporation
===========================================================================

- -----Original Message-----
From: Allen Chao [mailto:[email-masked]]
Sent: Thursday, August 14, 2003 12:51 PM
To: [email-masked]
Subject: [IBIS-Users]DC Sweep for the pullup IV curve

Hi IBIS experts,
I have a question concerning the sweep. I have a 3.3V power supply for my
device. However, the logic high voltage is 0.4V and logic low is 0V for my
one of my outputs. Do I do the DC Sweep at the output from -3.3V to 6.6V
or -0.4V to 0.8V?

Thanks a lot for the help,

Allen Chao

|------------------------------------------------------------------
|For help or to subscribe/unsubscribe, email [email-masked]
|with just the appropriate command message(s) in the body:
|
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|  subscribe   ibis       <optional e-mail address, if different>
|  subscribe   ibis-users <optional e-mail address, if different>
|  unsubscribe ibis       <optional e-mail address, if different>
|  unsubscribe ibis-users <optional e-mail address, if different>
|
|or email a written request to [email-masked].
|
|IBIS reflector archives exist under:
|
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------------------------------

Date: Thu, 14 Aug 2003 16:28:15 -0700
From: "Tom Dagostino" <[email-masked]>
Subject: RE: [IBIS-Users]DC Sweep for the pullup IV curve

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One thing you need to consider.  This part (which I have no knowledge of)
may only swing from 0 to 0.4 but if it is placed with another part on the
same net that can swing further you should cover a wider region in your
model.  BTW, what logic family is this?

Tom Dagostino
Teraspeed Consulting Group LLC     Teraspeed Consulting Group LLC
2926 SE Yamhill St.                Device Modeling Division
Portland, OR 97214                 13610 SW Harness Lane
                                   Beaverton, OR 97008
http://www.teraspeed.com           503-430-1065 
[email-masked] 

- -----Original Message-----
From: [email-masked] [mailto:[email-masked]]On
Behalf Of Muranyi, Arpad
Sent: Thursday, August 14, 2003 4:07 PM
To: [email-masked]
Subject: RE: [IBIS-Users]DC Sweep for the pullup IV curve

Allen,

Strictly speaking the spec says the following:

| The stated voltage ranges for I-V tables cover the most common, single
| supply cases.  When multiple supplies are specified, the voltages shall
| extend similarly to values that handle practical extremes in reflected
wave
| simulations.
|  
...
| 2) Voltage Ranges:
|    Points for each table must span the voltages listed below:
|
|       Table                   Low Voltage             High Voltage
|       -----------             -----------             ------------
|       [Pulldown]              GND - POWER             POWER + POWER
|       [Pullup]                GND - POWER             POWER + POWER
|       [GND Clamp]             GND - POWER             GND + POWER
|       [POWER Clamp]           POWER                   POWER + POWER
|       [Series Current]        GND - POWER             GND + POWER
|       [Series MOSFET]         GND                     GND + POWER
|
|    As described in the [Pulldown Reference] keyword section, the I-V
tables
|    of the [Pullup] and the [POWER Clamp] structures are 'Vcc relative',
|    using the equation:  Vtable = Vcc - Voutput.
|
|    For example, a model with a 5 V power supply voltage should be
|    characterized between (0 - 5) = -5 V and (5 + 5) = 10 V; and a model
with
|    a 3.3 V power supply should be characterized between (0 - 3.3) = -3.3 V
|    and (3.3 + 3.3) = 6.6 V for the [Pulldown] table.
|
|    When tabulating output data for ECL type models, the voltage points
must
|    span the range of Vcc to Vcc - 2.2 V.  This range applies to both the
|    [Pullup] and [Pulldown] tables.  Note that this range applies ONLY when
|    characterizing an ECL output.
|
|    These voltage ranges must be spanned by the IBIS data.  Data derived
from
|    lab measurements may not be able to span these ranges as such and so
may
|    need to be extrapolated to cover the full range.  This data must not be
|    left for the simulator to provide.

So according to the spec you would need to do -3.3 to 6.6 V.  However,
this was written in the days when most buffers were switching rail to
rail, and most transmission lines were unterminated having a full
reflection.
The spec wanted to make sure that the IV curves would cover the voltage
range even if the waveforms double due to reflections.

Lately, the picture has changed, and we have more low voltage swing signals
and parallel terminated buses.  As a consequence buffers do not necessarily
switch rail to rail, and reflections are much smaller.  Even if we followed
the logic of full reflections, your model should be sufficient if it covered
- -0.4 to 0.8 V.  This would be officially not according to the spec, but
as far as I remember, the parser doesn't issue an error message, so you
should be OK.

I am dealing with similar situations in other cases too, and I am
actually considering writing a BIRD on this subject to clarify/change
the spec.

Arpad Muranyi
Intel Corporation
===========================================================================

- -----Original Message-----
From: Allen Chao [mailto:[email-masked]]
Sent: Thursday, August 14, 2003 12:51 PM
To: [email-masked]
Subject: [IBIS-Users]DC Sweep for the pullup IV curve

Hi IBIS experts,
I have a question concerning the sweep. I have a 3.3V power supply for my
device. However, the logic high voltage is 0.4V and logic low is 0V for my
one of my outputs. Do I do the DC Sweep at the output from -3.3V to 6.6V
or -0.4V to 0.8V?

Thanks a lot for the help,

Allen Chao

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------------------------------

Date: Thu, 14 Aug 2003 18:06:25 -0700
From: "Mirmak, Michael" <[email-masked]>
Subject: [IBIS-Users] Agenda, IBIS Open Forum Teleconference 8/22

		     IBIS Open Forum Meeting Agenda
			       for 8/22/03

           Bridge Number    Reservation #   Passcode
           1-916-356-2663       4           696-0504
            (International Dial-In: 1-617-801-9781)

All meetings are 8:00 AM to 9:55 AM Pacific Time.  When calling 
into the meeting, provide the reservation number and passcode at 
the automated prompts.  If asked by an operator, please request 
to join the IBIS Open Forum hosted by Michael Mirmak.

8:00 Check-In, Intros, Announcements                       Mirmak

     - Intros of New IBIS Participants, Meeting Quorum     Mirmak
     - Call for Patents (IBIS 4.0, 4.1, ICM)               Mirmak
     - Membership Update and Treasurers Report             Mirmak
     - Review of Previous Meeting's Minutes (and ARs)      Mirmak
         August 8 Open Forum Minutes
     - Miscellany/Announcements                            All
     - Press & Web Page Updates                            Huq, All
     - New Models Available, Library Update                Leventhal
     - Opens for New Issues                                All

8:15 Administrative and Project Discussions

     International/External Progress
     - IEC 62014-3 (ICEM) Integrated Circuits Electromagnetic 
       Model Proposal (IEC 93/67/NP IBIS 
       and EMC Simulation)                                 Perrin/Peters
     - JEDEC Committee Report                              Green

     PCB East Summit Planning                              Mirmak

     DesignCon 2004 Summit Planning                        Mirmak

     IBIS Version 4.0 Parser Status                        Mirmak/Peters

     IBIS Quality Committee Report                         Katz/Green

     IBIS Model Review Committee                           Green

     S2IBIS3 Status                                        Varma/Ross

     Web Page Redesign Discussion                          All,
Huq/Coyle

     New Administrative Issues                             All

8:45 Technical Discussion

     BIRD81.2 - Clarification of Clamp Table Use           Green/Haller
     - Call for vote 

     Clarification BIRD Discussion                         Mirmak
     - [Series MOSFET] and Vds
     - [Series Switch Groups] and function_table_group

     IBIS Version 4.1 Discussion                           All
     - [Ramp]/C_comp BIRD status

     ICM Specification Second Reading and Discussion       Mirmak, All
     - Call for vote on Sept. 12

     IBISCHK4 Status                                       Ross/Angulo
     - Missing tests for BUGs 68, 71, 73, 75, 76

     BUG80 - [Model Selector] and [Diff Pin] Ordering      Angulo

     Driver Schedule Clarification                         Muranyi
     - Subparameters ignored in scheduled models?

     New Technical Issues                                  All

9:50 Wrap Up and Next Meetings Plans                       Mirmak

9:55 Sign Off
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------------------------------

Date: Fri, 15 Aug 2003 13:32:10 -0400
From: "Ingraham, Andrew" <[email-masked]>
Subject: Re: [IBIS-Users] pullup/pulldown range LVDS

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MessageDr. Lynne Green gave this as an example:

> Example with 12mA end points in I-V data:
> -3.3V   -12m   | dummy end point
> 0.4V    -12m   | end point of actual operating region
>                      | normal data, up to 96 more lines
> 1.6V     12m   | end point of actual operating region
> 6.6V     12m   | dummy end point

Personally, and maybe this is just me, I hate it when the endpoints do =
not continue the slope of the measured (or simulated) data.

In the case above the regions <0.4V and >1.6V have zero slope.  Is this =
realistic?  Probably not.  Only part of the reason for the dummy end =
points is to satisfy the IBIS Parser.  But it is also there to tell the =
simulator SOMEthing about how your device really behaves, to get the =
simulator back on track when it wanders out into that region.

Personally I would prefer that you extrapolate the measured or simulated =
data points when picking the dummy end points.  If the =
measured/simulated data has a positive slope, pick dummy end points that =
are on that slope, or close to it.

Accuracy is less important when you are that far out of the normal =
operating region, as is giving the simulator the right ballpark idea.  =
If not, you might find that the circuit actually converges at 6V and =
then you'd be in trouble.

Regards,
Andy

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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD><TITLE>Message</TITLE>
<META content=3D"text/html; charset=3Diso-8859-1" =
http-equiv=3DContent-Type>
<META content=3D"MSHTML 5.00.2919.6307" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT size=3D2>Dr. Lynne Green gave this as an =
example:</FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT size=3D2>
<DIV><SPAN class=3D074355016-11082003><FONT color=3D#0000ff face=3DArial =
size=3D2>&gt;=20
Example with 12mA end points in I-V data:</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT color=3D#0000ff face=3DArial =
size=3D2>&gt;=20
- -3.3V&nbsp; &nbsp;-12m&nbsp;&nbsp; | dummy end point</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT color=3D#0000ff face=3DArial =
size=3D2>&gt;=20
0.4V&nbsp;&nbsp;&nbsp; -12m&nbsp;&nbsp; | end point of actual operating=20
region</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT color=3D#0000ff face=3DArial =
size=3D2>&gt;=20
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&=
nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=20
| normal data, up to 96 more lines</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT color=3D#0000ff face=3DArial =
size=3D2>&gt;=20
1.6V&nbsp;&nbsp;&nbsp; &nbsp;12m&nbsp;&nbsp; | end point of actual =
operating=20
region</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003><FONT color=3D#0000ff face=3DArial =
size=3D2>&gt;=20
6.6V&nbsp;&nbsp; &nbsp; 12m&nbsp;&nbsp; | dummy end =
point</FONT></SPAN></DIV>
<DIV><SPAN class=3D074355016-11082003></SPAN></FONT>&nbsp;</DIV></DIV>
<DIV><FONT size=3D2>Personally, and maybe this is just me, I&nbsp;hate =
it when the=20
endpoints do not continue the slope of the measured (or simulated)=20
data.</FONT></DIV>
<DIV><FONT size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT size=3D2>In the case above the regions &lt;0.4V and &gt;1.6V =
have zero=20
slope.&nbsp; Is this realistic?&nbsp; Probably not.&nbsp; Only part of =
the=20
reason for the dummy end points is to satisfy the IBIS Parser.&nbsp; But =
it is=20
also there to tell the simulator SOMEthing about how your device really =
behaves,=20
to get the simulator back on track&nbsp;when it wanders out into that=20
region.</FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT size=3D2>Personally I would prefer that you extrapolate the =
measured or=20
simulated data points when picking the dummy end points.&nbsp; If the=20
measured/simulated data has a&nbsp;positive slope, pick dummy end points =
that=20
are on that slope, or close to it.</FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT size=3D2>Accuracy is less important when you are that far out =
of the=20
normal operating region, as is giving the simulator the right ballpark=20
idea.&nbsp; If not, you might find that the circuit actually converges =
at 6V and=20
then you'd be in trouble.</FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT size=3D2>Regards,</FONT></DIV>
<DIV><FONT size=3D2>Andy</FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV>&nbsp;</DIV>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: =
0px; PADDING-LEFT: 5px; PADDING-RIGHT: =
0px">&nbsp;</BLOCKQUOTE></BODY></HTML>

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------------------------------

Date: Fri, 15 Aug 2003 15:35:59 -0400
From: "Mike LaBonte" <[email-masked]>
Subject: RE: [IBIS-Users] pullup/pulldown range LVDS

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MessageLet's clarify which curves we are flattening. Each characteristic
(high state V/I and low state V/I) is split up into 3 separate curves that
must be combined mathematically by the simulator, and the curves can have
overlapping voltage ranges. At each voltage point the simulator has to add
the current of all 3 curves. But at any given voltage, only 1 or 2 of the
curves has data. The simulator has to extrapolate the other curves to see
what their current would be at the given voltage, assuming the slope at the
end continues on. Alternatively it could assume zero current at all points
beyond the ends of the curves. But the right approach depends on what the
model generator had in mind. For example, s2ibis2 generates curves that
*usually* fall to zero current at the ends, and it "believes" that the
current remains at zero beyond the ends. If it produces curves that do not
fall to zero at the ends, the IBIS model does not work right when an
extrapolating simulator adds the curves together. The end flattening method
that Lynne presents is derived from the way of making it so that the same
result is achieved in either type of simulator, if the current falls to zero
at the end.

Given that, the 2 clamp curves should be flattened at the inner ends to zero
current and slope, and the pullup and pulldown curves should have some
non-zero slope as Andy suggests. Otherwise, current would be constant in the
region between the driver voltage swing and VCC, because the clamps
contribute nothing there. That is not realistic, and simulators might not do
the right thing. Continuing the last known slope is preferable, but if it
results in a final current value at -VCC and 2VCC that the parser doesn't
like, it seems like reducing the slope wouldn't hurt. After all, the
simulation is not expected to go there, and in fact the device is probably
not designed to go there. If a V/I point is altered (in a forest :-) and no
one simulates it, was it ever altered?

Mike LaBonte
  -----Original Message-----
  From: [email-masked] [mailto:[email-masked]]On Behalf
Of Ingraham, Andrew
  Sent: Friday, August 15, 2003 1:32 PM
  To: [email-masked]
  Subject: Re: [IBIS-Users] pullup/pulldown range LVDS

  Dr. Lynne Green gave this as an example:

  > Example with 12mA end points in I-V data:
  > -3.3V   -12m   | dummy end point
  > 0.4V    -12m   | end point of actual operating region
  >                      | normal data, up to 96 more lines
  > 1.6V     12m   | end point of actual operating region
  > 6.6V     12m   | dummy end point

  Personally, and maybe this is just me, I hate it when the endpoints do not
continue the slope of the measured (or simulated) data.

  In the case above the regions <0.4V and >1.6V have zero slope.  Is this
realistic?  Probably not.  Only part of the reason for the dummy end points
is to satisfy the IBIS Parser.  But it is also there to tell the simulator
SOMEthing about how your device really behaves, to get the simulator back on
track when it wanders out into that region.

  Personally I would prefer that you extrapolate the measured or simulated
data points when picking the dummy end points.  If the measured/simulated
data has a positive slope, pick dummy end points that are on that slope, or
close to it.

  Accuracy is less important when you are that far out of the normal
operating region, as is giving the simulator the right ballpark idea.  If
not, you might find that the circuit actually converges at 6V and then you'd
be in trouble.

  Regards,
  Andy

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</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN =
class=3D504384218-15082003>Let's=20
clarify which curves we are flattening. Each characteristic (high state =
V/I and=20
low state V/I) is split up into 3 separate curves that must be combined=20
mathematically by the simulator, and the curves can have overlapping =
voltage=20
ranges. At each voltage point the simulator has to add the current of =
all 3=20
curves. But at any given voltage, only 1 or 2 of the curves has data. =
The=20
simulator has to extrapolate the other curves to see what their current =
would be=20
at the given voltage, assuming the slope at the end continues on. =
Alternatively=20
it could assume zero current at all points beyond the ends of the =
curves.=20
</SPAN></FONT><FONT face=3DArial color=3D#0000ff size=3D2><SPAN=20
class=3D504384218-15082003>But the right approach depends on what the =
model=20
generator had in mind. For example, s2ibis2 generates curves that =
*usually* fall=20
to zero current at the ends, and it "believes" that the current remains =
at zero=20
beyond the ends. If it produces curves that do not fall to zero at the =
ends, the=20
IBIS model does not work right when an extrapolating simulator adds the =
curves=20
together. The end flattening method that Lynne presents is&nbsp;derived =
from=20
the&nbsp;way of making it so that the same result is achieved =
in&nbsp;either=20
type of&nbsp;simulator, if the current falls to zero at the=20
end.</SPAN></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN=20
class=3D504384218-15082003></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN =
class=3D504384218-15082003>Given=20
that, the 2 clamp curves should be flattened at the inner ends to zero =
current=20
and slope, and the pullup and pulldown curves should have some non-zero =
slope as=20
Andy suggests. Otherwise, current would be constant in the region =
between the=20
driver voltage swing and VCC, because the clamps contribute nothing =
there. That=20
is not realistic, and simulators might not do the right thing.=20
</SPAN></FONT><FONT face=3DArial color=3D#0000ff size=3D2><SPAN=20
class=3D504384218-15082003>Continuing the last known slope is =
preferable, but if=20
it results in a final&nbsp;current value at -VCC and 2VCC that the =
parser=20
doesn't like, it seems like reducing the slope wouldn't hurt. After all, =
the=20
simulation is not expected to go there, and in fact the device is =
probably not=20
designed to go there. If a V/I point is altered (in a forest :-) and no =
one=20
simulates it, was it ever altered?</SPAN></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN=20
class=3D504384218-15082003></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN =
class=3D504384218-15082003>Mike=20
LaBonte</SPAN></FONT></DIV>
<BLOCKQUOTE dir=3Dltr style=3D"MARGIN-RIGHT: 0px">
  <DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
  size=3D2>-----Original Message-----<BR><B>From:</B> =
[email-masked]=20
  [mailto:[email-masked]]<B>On Behalf Of </B>Ingraham,=20
  Andrew<BR><B>Sent:</B> Friday, August 15, 2003 1:32 PM<BR><B>To:</B>=20
  [email-masked]<BR><B>Subject:</B> Re: [IBIS-Users] pullup/pulldown =
range=20
  LVDS<BR><BR></FONT></DIV>
  <DIV><FONT size=3D2>Dr. Lynne Green gave this as an =
example:</FONT></DIV>
  <DIV>&nbsp;</DIV>
  <DIV><FONT size=3D2>
  <DIV><SPAN class=3D074355016-11082003><FONT face=3DArial =
color=3D#0000ff size=3D2>&gt;=20
  Example with 12mA end points in I-V data:</FONT></SPAN></DIV>
  <DIV><SPAN class=3D074355016-11082003><FONT face=3DArial =
color=3D#0000ff size=3D2>&gt;=20
  -3.3V&nbsp; &nbsp;-12m&nbsp;&nbsp; | dummy end =
point</FONT></SPAN></DIV>
  <DIV><SPAN class=3D074355016-11082003><FONT face=3DArial =
color=3D#0000ff size=3D2>&gt;=20
  0.4V&nbsp;&nbsp;&nbsp; -12m&nbsp;&nbsp; | end point of actual =
operating=20
  region</FONT></SPAN></DIV>
  <DIV><SPAN class=3D074355016-11082003><FONT face=3DArial =
color=3D#0000ff size=3D2>&gt;=20
  =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&=
nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=20
  | normal data, up to 96 more lines</FONT></SPAN></DIV>
  <DIV><SPAN class=3D074355016-11082003><FONT face=3DArial =
color=3D#0000ff size=3D2>&gt;=20
  1.6V&nbsp;&nbsp;&nbsp; &nbsp;12m&nbsp;&nbsp; | end point of actual =
operating=20
  region</FONT></SPAN></DIV>
  <DIV><SPAN class=3D074355016-11082003><FONT face=3DArial =
color=3D#0000ff size=3D2>&gt;=20
  6.6V&nbsp;&nbsp; &nbsp; 12m&nbsp;&nbsp; | dummy end =
point</FONT></SPAN></DIV>
  <DIV><SPAN class=3D074355016-11082003></SPAN></FONT>&nbsp;</DIV></DIV>
  <DIV><FONT size=3D2>Personally, and maybe this is just me, I&nbsp;hate =
it when=20
  the endpoints do not continue the slope of the measured (or simulated) =

  data.</FONT></DIV>
  <DIV><FONT size=3D2></FONT>&nbsp;</DIV>
  <DIV><FONT size=3D2>In the case above the regions &lt;0.4V and =
&gt;1.6V have=20
  zero slope.&nbsp; Is this realistic?&nbsp; Probably not.&nbsp; Only =
part of=20
  the reason for the dummy end points is to satisfy the IBIS =
Parser.&nbsp; But=20
  it is also there to tell the simulator SOMEthing about how your device =
really=20
  behaves, to get the simulator back on track&nbsp;when it wanders out =
into that=20
  region.</FONT></DIV>
  <DIV>&nbsp;</DIV>
  <DIV><FONT size=3D2>Personally I would prefer that you extrapolate the =
measured=20
  or simulated data points when picking the dummy end points.&nbsp; If =
the=20
  measured/simulated data has a&nbsp;positive slope, pick dummy end =
points that=20
  are on that slope, or close to it.</FONT></DIV>
  <DIV>&nbsp;</DIV>
  <DIV><FONT size=3D2>Accuracy is less important when you are that far =
out of the=20
  normal operating region, as is giving the simulator the right ballpark =

  idea.&nbsp; If not, you might find that the circuit actually converges =
at 6V=20
  and then you'd be in trouble.</FONT></DIV>
  <DIV>&nbsp;</DIV>
  <DIV><FONT size=3D2>Regards,</FONT></DIV>
  <DIV><FONT size=3D2>Andy</FONT></DIV>
  <DIV>&nbsp;</DIV>
  <DIV>&nbsp;</DIV>
  <BLOCKQUOTE=20
  style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: =
0px">&nbsp;</BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>

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