Subject: ibis-users V1 #12
From: owner-ibis-users@ (ibis-users)
To: [email-masked]

ibis-users        Wednesday, November 20 2002        Volume 01 : Number 012

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

Date: Tue, 12 Nov 2002 09:07:07 -0500
From: "Ingraham, Andrew" <[email-masked]>
Subject: RE: [IBIS-Users] C_comp issue?

> I think we also agree that when we simulate with a particular
> IBIS model, then no matter what the C_comp parameter says, the
> output should reproduce the same waveforms when the model is
> driving and no reflections are present.
 
On a purely theoretical level, surely there are limits to that.

You should not be able to increase C_comp without bounds and
still have the same waveforms.  The V-T waveforms, C_comp, and
the transistor drive strengths (from their I-V curves) ought to be a
consistent family, and stressing one of them while not changing
the others, eventually hits a wall.

Even if you don't stress it that far to make the algorithms break,
there's no guarantee that the waveforms wouldn't be affected by
even small changes in C_comp, when the load is anything other
than R_fixture to V_fixture.

Regards,
Andy

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

Date: Tue, 12 Nov 2002 16:24:38 +0100
From: [email-masked]
Subject: [IBIS-Users] Questions about Bus Hold (2nd try)

Hello Ibis collegues,

I want to make accurate IBIS models for input buffers and I/O buffers with bus hold.
Existing models, I have seen on the web, show the bus hold characteristic in the ground clamp curve.
When running the IBIS checker, this causes non-monotonic warnings.
Therefore I am not sure whether this way of modeling is correct.

This brings me to the following questions:

1. If the bushold characteristic is present in the ground clamp curve, how would you qualify this:
1a Wrong, since it causes non-monotonic warnings
1b. Useless
1c. Okay, since it represents the actual behavior.
1d. Other ....

2. The IBIS standard describes the Bus Hold Submodel.
I assume the Top Model describes the buffer without bus hold characteristic.
From the IBIS standard I cannot understand what part of the circuit I must simulate in order to gather the data for the Bus Hold Submodel, namely the pullup, pulldown and last but not least the ramp figures.

Of course those who have designed the IBIS standard must know the idea behind the Submodel.
Therefore I would appreciate it very much if somebody could tell me:
2.1 Which part of the circuit is described by the sub model?
2.2 How can I get more information about this subject?

Thank you in anticipation for your reactions.

Kind regards,

Rob

________________________________________________________
Rob Mataheroe                                               Philips Semiconductors bv
P.G. Logic Product Group PD&S               Building AM1.108
Senior Design Modeling Engineer           Gerstweg 2
Tel. ++31 (0)24 353 2370                                6534 AE Nijmegen
Fax. ++31 (0)24 353 2820                                The Netherlands
Email: [email-masked]

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

Date: Tue, 12 Nov 2002 08:56:51 -0800
From: "Muranyi, Arpad" <[email-masked]>
Subject: RE: [IBIS-Users] Questions about Bus Hold (2nd try)

Rob,

I am a little bit confused about what you want to do.  Here is why:
The intent of having the bus hold submodels was to make it possible
to simulate a structure in which two inverters are connected back to back
so that the first inverter's input is tied to the second inverter's output
which is also the die pad.  (The two inverters are connected in series,
i.e. the output of the first stage is connected to the input of the
second stage).

This structure can be used as a receiver, or it can be connected 
parallel with an I/O buffer.  Either way, it works effectively as
a termination to the line, except it doesn't draw a lot of DC current
while the signal is held in one state or the other for a long time
because it switches to the same state.  The only criteria you need to
watch is that the buffer that drives the signal must be stronger than
this hold circuit, so that it can pull it out of one state and push it
into the other state when a transition is happening.

So, the pad is driven by the second inverter, and you can model it with
normal IBIS modeling techniques.  However, in order to get it's IV curves
you may want to remove the loop and tie the input of the first inverter
to high or low so that it doesn't switch while you are sweeping the IV
curve.  Then you would also want to make Vt curves, which you would do
by applying the waveform that this device usually gets on the pad to the
input of the first stage.  Using R_fixture and V_ficture on the output
of the second stage you get the IBIS waveforms.  The only additional
thing you need are the threshold voltages that tells the simulator when to
start switching (this is basically the same as finding the actual Vinh and
Vinl for the first inverter).

From this you can see that the clamps are not the most important part of
this kind of a submodel, so I am not sure why those models you have seen
use clamps to describe the bus hold characteristics.

Now, if you are talking about the "Dynamic clamp" submodels than it is
the clamps that are of interest, but you didn't ask about that, so I won't
go into that for now.

I know I didn't answer all of your questions, but I wanted to clarify this
first.  Once we are in synch on this we can go to the rest of your questions
(if you still have any).

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

- -----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Tuesday, November 12, 2002 7:25 AM
To: [email-masked]
Subject: [IBIS-Users] Questions about Bus Hold (2nd try)

Hello Ibis collegues,

I want to make accurate IBIS models for input buffers and I/O buffers with bus hold.
Existing models, I have seen on the web, show the bus hold characteristic in the ground clamp curve.
When running the IBIS checker, this causes non-monotonic warnings.
Therefore I am not sure whether this way of modeling is correct.

This brings me to the following questions:

1. If the bushold characteristic is present in the ground clamp curve, how would you qualify this:
1a Wrong, since it causes non-monotonic warnings
1b. Useless
1c. Okay, since it represents the actual behavior.
1d. Other ....

2. The IBIS standard describes the Bus Hold Submodel.
I assume the Top Model describes the buffer without bus hold characteristic.
From the IBIS standard I cannot understand what part of the circuit I must simulate in order to gather the data for the Bus Hold Submodel, namely the pullup, pulldown and last but not least the ramp figures.

Of course those who have designed the IBIS standard must know the idea behind the Submodel.
Therefore I would appreciate it very much if somebody could tell me:
2.1 Which part of the circuit is described by the sub model?
2.2 How can I get more information about this subject?

Thank you in anticipation for your reactions.

Kind regards,

Rob

________________________________________________________
Rob Mataheroe                                               Philips Semiconductors bv
P.G. Logic Product Group PD&S               Building AM1.108
Senior Design Modeling Engineer           Gerstweg 2
Tel. ++31 (0)24 353 2370                                6534 AE Nijmegen
Fax. ++31 (0)24 353 2820                                The Netherlands
Email: [email-masked]
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------------------------------

Date: Wed, 13 Nov 2002 21:46:57 +0100
From: "Perrin, Jean-Claude" <[email-masked]>
Subject: RE: [IBIS-Users] IBIS Package Model with Multiple Ground Planes a nd Redundant Port s

This message is in MIME format. Since your mail reader does not understand
this format, some or all of this message may not be legible.

- ------_=_NextPart_001_01C28B55.CE5CBB60
Content-Type: text/plain;
	charset="iso-8859-1"

Mike.
 I think the best is to consider each bloc i/o with the same power supply as
an identity with its own IBIS model .
after the best is add parasitic elements due to bonding and package
connections and after is to consider each bloc is grounded to same power
plan (PCB) through 
these parasitic element .
we have multiground plan as at the chip but it is mandatory for
communication to have a single plane in witch flow all return currents.
I am not sure to be right..
Best Regards
Jean claude Perrin 

[Perrin, Jean-Claude]  -----Original Message-----
From: Lamson, Mike 
Sent: Monday, November 11, 2002 9:45 PM
To: [email-masked]
Subject: [IBIS-Users] IBIS Package Model with Multiple Ground Planes and
Redundant Port s

How can an IBIS package model be constructed with multiple ground planes
that have the same input ports at the chip and the same output ports at the
package ball?  That is, there are two current paths starting at the same
chip bump and going to the same package ball but on different planes.  Does
anyone have an example?

Mike Lamson 

- ------_=_NextPart_001_01C28B55.CE5CBB60
Content-Type: text/html;
	charset="iso-8859-1"

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<TITLE>IBIS Package Model with Multiple Ground Planes and Redundant Ports</TITLE>

<META content="MSHTML 5.50.4522.1800" name=GENERATOR></HEAD>
<BODY>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=332524320-13112002>Mike.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=332524320-13112002>&nbsp;I think the best is to consider each bloc i/o 
with the same power supply as an identity with its own IBIS model 
.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=332524320-13112002>after 
the best is add parasitic elements due to bonding and package connections and 
after is to consider each bloc is grounded to same power plan (PCB) 
through&nbsp;</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=332524320-13112002>these 
parasitic element .</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=332524320-13112002>we 
have multiground plan as at the chip but it is mandatory for communication to 
have a single plane in witch flow all return currents.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=332524320-13112002>I am 
not sure to be right..</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=332524320-13112002>Best 
Regards</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=332524320-13112002>Jean 
claude Perrin&nbsp;</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff><SPAN 
class=332524320-13112002></SPAN></FONT><FONT face=Tahoma><BR><FONT size=2><SPAN 
class=332524320-13112002><FONT face=Arial color=#0000ff>[Perrin, 
Jean-Claude]&nbsp;&nbsp;</FONT></SPAN>-----Original Message-----<BR><B>From:</B> 
Lamson, Mike <BR><B>Sent:</B> Monday, November 11, 2002 9:45 PM<BR><B>To:</B> 
[email-masked]<BR><B>Subject:</B> [IBIS-Users] IBIS Package Model with 
Multiple Ground Planes and Redundant Port s<BR><BR></FONT></DIV></FONT>
<BLOCKQUOTE>
  <P><FONT face=Arial size=2>How can an IBIS package model be constructed with 
  multiple ground planes that have the same input ports at the chip and the same 
  output ports at the package ball?&nbsp; That is, there are two current paths 
  starting at the same chip bump and going to the same package ball but on 
  different planes.&nbsp; Does anyone have an example?</FONT></P>
  <P><FONT face=Arial size=2>Mike Lamson</FONT> 
</P><BR></BLOCKQUOTE></BODY></HTML>

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

Date: Wed, 13 Nov 2002 12:56:00 -0800
From: Eric Hsu <[email-masked]>
Subject: [IBIS-Users] Compatibility for ver2.1 and ver3.2?

Hi all,

Does ver2.1 provide option [Model Selector] and [Diff Pin]? If not, can
I use "s2ibis2" to generate multiple ibis models(ver2.1), and put them
together but just adding those function to become ver3.2?

- -eric

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

Date: Wed, 13 Nov 2002 15:37:53 -0800
From: "Angulo, John" <[email-masked]>
Subject: [IBIS-Users] s2ibis2 for windows voltage steps problem

The following is posted on behalf of Henrik G. Madsen of Vitesse Semiconductor.  Please send any private replies to [email-masked] only.

- ---------------------------------------
Hey

I'm using s2ibis2 for windows to generate my IBIS model.
I have used both the Win95 and NT version found at the IBIS site
http://www.eda.org/pub/ibis/s2ibis/s2ibis2_nt/

But it seems that the tool has problems with 'interpreting' the resulting .LIS files and generating the IBIS file.

Depending on the supply voltage (or maybe the number of original measurement point) it reduces the number of available measurement points in the IBIS file, leaves 'holes' in the voltage steps, or repeat specific voltage steps, while leaving others out.

Do there exist a workaround or fix for that?

I have included three examples below, where I use the pulldown curves as example. Dumps from the IBIS files can be found in the end of this mail. I have removed voltage steps of no interest in the middle to reduce size and ease location of issue.

Example 1, 3.3V buffer
The HSPICE .LIS file includes 
0.1V steps from -3.3 to 6.6V (100 points in total)
s2ibis2 reduces this to 74 points (see gencpu_io_3v3 model below). It's OK, but why not keep the 100 original points

Example 2, 2.5V buffer
Same buffer as example 1, but with a 2.5V supply voltage
The HSPICE .LIS file includes
50mV steps from -2.5V to 5.0V (151 points in total)
s2ibis2 reduces this to 101 points, i.e.. above 100 point limit. (see gencpu_io_2v5 model below). The real pain is that it keeps the 50mV step but leaves holes in the steps between -2.05V and -1.00V, and again between 3.95V and 5.0V. I know that this is not the most important area, but I would prefer no holes but larger steps in the outer area.

Example 3, 1.5V buffer
The HSPICE .LIS file includes
50mV step from -1.5V to 3.0V (91 points)
s2ibis2 keeps the 91 points, but duplicates the -1.5V and 2.5V measurements 9 times, i.e.. corrupting the IBIS file between -1.5V to -1.0V and 2.5V to 3.0V. (see hstl1_out model below).

|************************************************************************
|                          Model gencpu_io_3v3
|************************************************************************
|
[Model]          gencpu_io_3v3
Model_type       I/O
Polarity         Non-Inverting
Enable           Active-High
Vinl =   0.80000V
Vinh =   2.00000V
Vmeas =   1.65000V
Cref =  10.00000pF
C_comp           1.080pF               NA                  NA     
|
|
[Temperature Range]       55.000              0.120k              0.0000
[Voltage Range]           3.300V              3.000V              3.600V
[Pulldown]
| voltage     I(typ)              I(min)              I(max)
|
  -3.30000       -1.00000mA         0.0000A              -2.00000mA
  -3.10000       -1.00000mA         0.0000A              -2.00000mA
  -2.90000       -1.00000mA          -1.00000mA          -2.00000mA
  -2.70000       -1.00000mA          -1.00000mA          -2.00000mA
  -2.50000       -2.00000mA          -1.00000mA          -3.00000mA
  -2.30000       -2.00000mA          -1.00000mA          -4.00000mA
  -2.10000       -2.30000mA          -1.10000mA          -3.80000mA
  -1.90000       -2.90000mA          -1.30000mA          -5.90000mA
  -1.70000       -3.80000mA          -1.60000mA          -7.20000mA
  -1.50000       -4.90000mA          -2.10000mA          -8.80000mA
  -1.00000      -12.42000mA          -5.30000mA         -24.53000mA
  -0.90000      -17.92000mA          -7.15000mA         -32.89000mA
   ::::: 100mV step in voltages in removed point
   4.30000       57.75000mA          38.34000mA          84.39000mA
   4.50000       60.45000mA          41.38000mA          84.67000mA
   4.70000       64.06000mA          44.77000mA          86.87000mA
   4.90000       68.27000mA          48.14000mA          90.82000mA
   5.10000       72.97000mA          47.25000mA          95.72000mA
   5.30000       77.97000mA          41.09000mA           0.10130A
   5.50000       81.89000mA          40.18000mA           0.10750A
   5.70000       79.27000mA          40.93000mA           0.11410A
   5.90000       76.34000mA          42.39000mA           0.12090A
   6.10000       76.82000mA          44.36000mA           0.12490A
   6.60000       84.91000mA          51.24000mA           0.12820A

|************************************************************************
|                          Model gencpu_io_2v5
|************************************************************************
|
[Model]          gencpu_io_2v5
Model_type       I/O
Polarity         Non-Inverting
Enable           Active-High
Vinl =   0.70000V
Vinh =   1.70000V
Vmeas =   1.20000V
Cref =  10.00000pF
C_comp           1.080pF               NA                  NA     
|
|
[Temperature Range]       55.000              0.120k              0.0000
[Voltage Range]           2.500V              2.300V              2.700V
[Pulldown]
| voltage     I(typ)              I(min)              I(max)
|
  -2.50000       -1.00000mA         0.0000A              -2.00000mA
  -2.45000       -1.00000mA         0.0000A              -3.00000mA
  -2.40000       -2.00000mA          -1.00000mA          -3.00000mA
  -2.35000       -2.00000mA         0.0000A              -3.00000mA
  -2.30000       -1.00000mA          -1.00000mA          -3.00000mA
  -2.25000       -1.00000mA          -1.00000mA          -3.00000mA
  -2.20000       -2.00000mA         0.0000A              -3.00000mA
  -2.15000       -2.00000mA          -1.00000mA          -4.00000mA
  -2.10000       -1.80000mA          -0.80000mA          -3.80000mA
  -2.05000       -1.80000mA          -0.90000mA          -4.00000mA
  -1.00000      -10.09000mA          -4.10000mA         -20.71000mA
  -0.95000      -11.93000mA          -4.70000mA         -25.25000mA
  -0.90000      -14.57000mA          -5.57000mA         -28.86000mA
   :::::: 50mV step in voltages in removed points
   3.90000       43.48000mA          29.54000mA          60.96000mA
   3.95000       44.46000mA          30.34000mA          62.03000mA
   5.00000       46.10000mA          24.02000mA          91.11000mA

|************************************************************************
|                            Model hstl1_out
|************************************************************************
|
[Model]          hstl1_out
Model_type       Output
Polarity         Non-Inverting
Vmeas =   0.75000V
Cref =  10.00000pF
C_comp           0.600pF             0.550pF             0.650pF
|
|
[Temperature Range]       55.000              0.120k              0.0000
[Voltage Range]           1.500V              1.400V              1.600V
[Pulldown]
| voltage     I(typ)              I(min)              I(max)
|
  -1.50000       -0.48960A           -0.47430A           -0.50820A
  -1.50000       -0.48960A           -0.47430A           -0.50820A
  -1.50000       -0.48960A           -0.47430A           -0.50820A
  -1.50000       -0.48960A           -0.47430A           -0.50820A
  -1.50000       -0.48960A           -0.47430A           -0.50820A
  -1.50000       -0.48960A           -0.47430A           -0.50820A
  -1.50000       -0.48960A           -0.47430A           -0.50820A
  -1.50000       -0.48960A           -0.47430A           -0.50820A
  -1.50000       -0.48960A           -0.47430A           -0.50820A
  -1.50000       -0.48960A           -0.47430A           -0.50820A
  -1.00000       -0.15700A           -0.16210A           -0.15740A
  -0.95000       -0.13190A           -0.13650A           -0.13430A
  -0.90000       -0.11060A           -0.11320A           -0.11730A
   :::::: 50mV step in voltages in removed points
   2.40000       72.01000mA          68.98000mA          85.96000mA
   2.45000       78.52000mA          77.69000mA          90.01000mA
   2.50000       86.36000mA          88.34000mA          94.82000mA
   2.50000       86.36000mA          88.34000mA          94.82000mA
   2.50000       86.36000mA          88.34000mA          94.82000mA
   2.50000       86.36000mA          88.34000mA          94.82000mA
   2.50000       86.36000mA          88.34000mA          94.82000mA
   2.50000       86.36000mA          88.34000mA          94.82000mA
   2.50000       86.36000mA          88.34000mA          94.82000mA
   2.50000       86.36000mA          88.34000mA          94.82000mA
   2.50000       86.36000mA          88.34000mA          94.82000mA
   2.50000       86.36000mA          88.34000mA          94.82000mA
   3.00000        0.34700A            0.36010A            0.33770A

_____________________________________
Henrik G Madsen
Sr. HW Engineer 
Vitesse Semiconductor Corporation A/S
Ethernet Products Division
Hoerkaer 16,  DK-2730 Herlev, DENMARK
Direct: +45 4485 5920
Phone: +45 4485 5900, Fax: +45 4485 5901
mail: [email-masked]
web: http://www.vitesse.com
_____________________________________

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

Date: Thu, 14 Nov 2002 14:48:00 -0800 (PST)
From: Syed Huq <[email-masked]>
Subject: Re: [IBIS-Users] Compatibility for ver2.1 and ver3.2?

Not sure if you got your answer.

Yes you can create a v2.1 model, then add the [Model Selector] and [Diff 
pin] and call it a v3.2

This link will tell you that [Diff pin] is v2.1 and [Model Selector] is 
v3.2

http://www.vhdl.org/pub/ibis/ver3.2/tree3_2.txt

Syed

>Date: Wed, 13 Nov 2002 12:56:00 -0800
>From: Eric Hsu <[email-masked]>
>X-Accept-Language: zh-TW, en
>MIME-Version: 1.0
>To: [email-masked]
>Subject: [IBIS-Users] Compatibility for ver2.1 and ver3.2?
>Content-Transfer-Encoding: 7bit
>
>Hi all,
>
>Does ver2.1 provide option [Model Selector] and [Diff Pin]? If not, can
>I use "s2ibis2" to generate multiple ibis models(ver2.1), and put them
>together but just adding those function to become ver3.2?
>
>-eric
>
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------------------------------

Date: Fri, 15 Nov 2002 09:10:58 -0800
From: "Peters, Stephen" <[email-masked]>
Subject: [IBIS-Users] Agenda, IBIS Open Forum Teleconference, 11/22

		     IBIS Open Forum Meeting Agenda
			      for 11/22/02

		Bridge Number    Reservation #   Passcode
            1-916-356-2663      5            8435570

All meetings are 8:00 AM to 9:55 AM Pacific Time.  When you call into the 
meeting, ask for the IBIS Open Forum hosted by Stephen Peters and give the
Reservation Number and Passcode.

8:00 Check-In, Intros, Announcements                         Peters

     - Intros of New IBIS Participants, Meeting Quorum       Peters
     - Call for Patents                                      Peters
     - Membership Update and Treasurers Report               Peters
     - Review of Previous Meeting's Minutes (and ARs)        Peters
     - Miscellany/Announcements                              All
     - Press & Web Page Updates                              Huq, All
     - New Models Available, Library Update                  Leventhal, All
     - 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

     DesignCon2003 IBIS Summit Meeting Planning              Peters

     IBIS Version 4.0 Parser Funding                         Peters

     IBIS Quality Committee                                  Katz

     IBIS Model Review Committee                             Green

     New Administrative Issues                               All

8:45 Technical Discussion

     IBIS Connector and Futures Group Report                 Peters/Green
     - ICM Specification Proposal

     BIRD75.7 - Multi-Lingual IBIS Model Support             Ross/Muranyi
     BIRD77.2 - Differential Subparameter Additions          Ross

     BIRD78.1 - Comment Line Length Limit                    Green

     BIRD79 - Non-linear Buffer Impedance
Muranyi/Giacotto

     BIRD74.1 - EMI Parameters                               de Burgh

     ibischk3 Status                                         Ross
     - BUG71 - Monotonic Checking for Combined I-V Tables    Haller
     - BUG74 - Missing Timing Test Load Warning Messages     Haller
     - BUG76 - External Package Under Win32 Requires         Ross
               Writeable Root
     - BUG77 - Test for Series* Models in [Pin] Error        Ross

     New Technical Issues                                    All

9:50 Wrap Up and Next Meetings Plans                         Peters

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

Date: Fri, 15 Nov 2002 12:00:17 -0800
From: Monika Garg <[email-masked]>
Subject: [IBIS-Users] info on differential signals

Hello,

I am posting this question on behalf of my friend, Tessa ([email-masked]), Please reply to her directly. She is copied in the To list.

When using an IBIS model with a differential signals, if the signal is
not declared as differential we get warnings in compilation (Voh and Vol
not declared).  Will an IBIS model that fails to declare signals as
differential give an accurate representation of these signals?  Is there
any reason not to declare differential signals as differential
(backwards compatibility)?

Thanks in advance for all the help.
Regards
Monika

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

Date: Fri, 15 Nov 2002 13:51:59 -0800
From: "Tom Dagostino" <[email-masked]>
Subject: RE: [IBIS-Users] info on differential signals

The diff table's Vdiff will override the Vinl, Vinh data in the IBIS model.
So, if the model does not have the diff table then the simulator will look
for Vinl, Vinh.   If the diff table is present then the simulator will use
Vdiff. If the pin pairs are differential and you do not declare them as such
then the simulator has no way of knowing that the differential threshold
should be applied nor, in the case of differential outputs, will it know to
differentially stimulate the driver pairs.

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

- -----Original Message-----
From: [email-masked]
[mailto:[email-masked]]On Behalf Of Monika Garg
Sent: Friday, November 15, 2002 12:00 PM
To: [email-masked]; Tessa Trethewey
Subject: [IBIS-Users] info on differential signals

Hello,

I am posting this question on behalf of my friend, Tessa ([email-masked]),
Please reply to her directly. She is copied in the To list.

When using an IBIS model with a differential signals, if the signal is
not declared as differential we get warnings in compilation (Voh and Vol
not declared).  Will an IBIS model that fails to declare signals as
differential give an accurate representation of these signals?  Is there
any reason not to declare differential signals as differential
(backwards compatibility)?

Thanks in advance for all the help.
Regards
Monika

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

Date: Fri, 15 Nov 2002 16:18:09 -0800
From: Eric Hsu <[email-masked]>
Subject: [IBIS-Users] Question about warning message

Hi All,

When running ibischk3 to check ver2.1 model, if there are warning
messages complaining about "non-monotonic"and "extreme currents present"
around hundred amp level, is it possible and acceptible?

Thanks

~eric

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

Date: Fri, 15 Nov 2002 16:32:40 -0800
From: "Muranyi, Arpad" <[email-masked]>
Subject: RE: [IBIS-Users] Compatibility for ver2.1 and ver3.2?

Eric,

[Model Selector] is a 3.2 feature, but [Diff Pin] was available in 2.1.
Yes, you can put the models together like that.

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

- -----Original Message-----
From: Eric Hsu [mailto:[email-masked]]
Sent: Wednesday, November 13, 2002 12:56 PM
To: [email-masked]
Subject: [IBIS-Users] Compatibility for ver2.1 and ver3.2?

Hi all,

Does ver2.1 provide option [Model Selector] and [Diff Pin]? If not, can
I use "s2ibis2" to generate multiple ibis models(ver2.1), and put them
together but just adding those function to become ver3.2?

- -eric

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

Date: Fri, 15 Nov 2002 16:40:08 -0800
From: Kim Helliwell <[email-masked]>
Subject: Re: [IBIS-Users] Question about warning message

The "Nonmonotonic" warnings may or may not be acceptable,
but are quite common. It depends on how serious the nonmonotonicity
is, and whether it is only in the individual curves or in the summed
curves (which is what your simulator will be using). Many simulators
will smooth out the nonmonotonic behavior they find, so it may
not be a real issue unless it's egregious.

The "extreme currents present" is less common, but still occurs
more than one would like. I personally don't find it acceptable, since
it can easily be avoided. If you're getting this, it's a good idea to
check that your simulation results are yielding expected answers.

On Friday, November 15, 2002, at 04:18  PM, Eric Hsu wrote:

> Hi All,
>
> When running ibischk3 to check ver2.1 model, if there are warning
> messages complaining about "non-monotonic"and "extreme currents 
> present"
> around hundred amp level, is it possible and acceptible?
>
> Thanks
>
> ~eric
>
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>
>
Kim Helliwell
Apple Computer
[email-masked]
408 974 9936

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

Date: Fri, 15 Nov 2002 23:31:46 -0800 (PST)
From: "Abdulrahman A. Rafiq" <[email-masked]>
Subject: Re: [IBIS-Users] Question about warning message

- --0-1075236207-1037431906=:44246
Content-Type: text/plain; charset=us-ascii

Eric, 
The warning message of "non-monotonic" is perfectly acceptable and can be ignored. As for the warning message of extrreme currents present, it also is acceptable. In fact if you open the .ibs file and comment our all the extreme +ve and -ve currents in the I-V tables and then rerun ibischks, this warning message will not show up. 
In short you needn't worry too much about these warnings.
Hope this helps.
Regards, 
Abdulrahman Rafiq
 Eric Hsu <[email-masked]> wrote:Hi All,

When running ibischk3 to check ver2.1 model, if there are warning
messages complaining about "non-monotonic"and "extreme currents present"
around hundred amp level, is it possible and acceptible?

Thanks

~eric

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************************************
ABDULRAHMAN AK RAFIQ
Scientific Engineering Consultants, Inc
Phone: (805) 708-1976
Email: [email-masked] 
URL: www.geocities.com/arafiqsi/ 
************************************

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- --0-1075236207-1037431906=:44246
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<P>Eric, 
<P>The warning message of "non-monotonic" is perfectly acceptable and can be ignored. As for the warning message of extrreme currents present, it also is acceptable. In fact if you open the .ibs file and comment our all the extreme +ve and -ve currents in the I-V tables and then rerun ibischks, this warning message will not show up. 
<P>In short you needn't worry too much about these warnings.
<P>Hope this helps.
<P>Regards, 
<P>Abdulrahman Rafiq
<P>&nbsp;<B><I>Eric Hsu &lt;[email-masked]&gt;</I></B> wrote:
<BLOCKQUOTE style="BORDER-LEFT: #1010ff 2px solid; MARGIN-LEFT: 5px; PADDING-LEFT: 5px">Hi All,<BR><BR>When running ibischk3 to check ver2.1 model, if there are warning<BR>messages complaining about "non-monotonic"and "extreme currents present"<BR>around hundred amp level, is it possible and acceptible?<BR><BR>Thanks<BR><BR>~eric<BR><BR>|------------------------------------------------------------------<BR>|For help or to subscribe/unsubscribe, email [email-masked]<BR>|with just the appropriate command message(s) in the body:<BR>|<BR>| help<BR>| subscribe ibis <OPTIONAL different if address, e-mail><BR>| subscribe ibis-users <OPTIONAL different if address, e-mail><BR>| unsubscribe ibis <OPTIONAL different if address, e-mail><BR>| unsubscribe ibis-users <OPTIONAL different if address, e-mail><BR>|<BR>|or email a written request to [email-masked].<BR>|<BR>|IBIS reflector archives exist under:<BR>|<BR>| http://www.eda.org/pub/ibis/email_archive/ Recent<BR>| http://www.eda.org/pub/ibis/users_archive/ Recent<BR>| http://www.eda.org/pub/ibis/email/ E-mail since 1993</BLOCKQUOTE><BR><BR>************************************<br>ABDULRAHMAN AK RAFIQ<br>Scientific Engineering Consultants, Inc<br>Phone: (805) 708-1976<br>Email: [email-masked] <br>URL: www.geocities.com/arafiqsi/ <br>************************************<p><br><hr size=1>Do you Yahoo!?<br>
<a href="http://rd.yahoo.com/hosting/mailsig/*http://webhosting.yahoo.com">Yahoo! Web Hosting</a> - Let the expert host your site
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------------------------------

Date: Mon, 18 Nov 2002 07:56:32 -0500
From: "Ingraham, Andrew" <[email-masked]>
Subject: RE: [IBIS-Users] Question about warning message

The warning about "extreme currents" probably means that you started
with inaccurate SPICE models.

The clamp diodes might be modeled (in SPICE) with unrealistically small,
or zero, series resistances, causing huge simulated currents at large
voltages beyond the supply rails.

Is it a problem?  Yes and no.  Most simulations shouldn't stray far into
these regions, and if they do, the huge currents generally steer things
back away from them.  But it might mean that the simulated results do
not correctly show what happens in response to normal overshoot
transients.

The best way to fix it, is to correct the SPICE model, and start over.
Or measure how the device actually behaves and modify one or both models
accordingly.

Regards,
Andy

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

Date: Mon, 18 Nov 2002 15:26:45 +0100
From: "Henrik G. Madsen" <[email-masked]>
Subject: RE: [IBIS-Users] Question about warning message

If you have access to the Spice models, the below will normally solve the issue.

The BSIM3V3.x transistor model includes two sidewall diodes, one at the source and one at the drain terminal.
The Spice model (at least HSPICE) do not include any loss for these parasitic diodes.
As a consequence, a lot of current will begin flowing through these parasitic diodes, when a signal outside the rail voltages is applied to the PAD of the IO cell.

It is possible to 'turn off' the parasitic diodes in the BSIM3V3 NMOS/PMOS models by setting the below parameters to zero. This should only be done for the transistors closest to PAD in the I/O cell.

>  Set JSW=0, CJ=0,  CJSW=0,  JS=0
Afterwards two discrete diodes should be added with the same size as the
transistor's source and drain terminal to include equivalent models of lossy diodes as the ones removed.

See example below
MTEST Drain Gate Source Bulk NCH3 L=0.50 W=28.00 AD=AreaD
+ PD=PerD AS=AreaS PS=PerS NRS=0.004 NRD=0.008

Becomes
MTEST Drain Gate Source Bulk NCH3_esd L=0.50 W=28.00 AD=AreaD
+ PD=PerD AS=AreaS PS=PerS NRS=0.004 NRD=0.008
dMTESTd Bulk Drain  Diode area=AreaD PJ=PerD
dMTESTs Bulk Source Diode area=AreaS PJ=PerS

Where NCH3_esd is the same transistor as NCH3 except for that JSW=0,
CJ=0, CJSW=0, JS=0

/Henrik
- -----Original Message-----
From: Ingraham, Andrew [mailto:[email-masked]]
Sent: 18. november 2002 13:57
To: [email-masked]
Subject: RE: [IBIS-Users] Question about warning message

The warning about "extreme currents" probably means that you started
with inaccurate SPICE models.

The clamp diodes might be modeled (in SPICE) with unrealistically small,
or zero, series resistances, causing huge simulated currents at large
voltages beyond the supply rails.

Is it a problem?  Yes and no.  Most simulations shouldn't stray far into
these regions, and if they do, the huge currents generally steer things
back away from them.  But it might mean that the simulated results do
not correctly show what happens in response to normal overshoot
transients.

The best way to fix it, is to correct the SPICE model, and start over.
Or measure how the device actually behaves and modify one or both models
accordingly.

Regards,
Andy

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|or email a written request to [email-masked].
|
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|
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------------------------------

Date: Mon, 18 Nov 2002 10:27:51 -0800
From: "Angulo, John" <[email-masked]>
Subject: RE: [IBIS-Users] Question about warning message

The following is posted on behalf of Tom Dagostino at Teraspeed Consulting Group.  Please send any private replies to [email-masked] only.

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

I'll disagree on this.  The extreme currents are likely OK but the
non-monotonic warnings may cause the simulations to not converge properly or
in some simulators cause the model not to load at all.  If the sum of the IV
curves do not have monotonic issues you are OK.  If the sum of the curves do
have monotonic issues I would investigate before I would say it is OK.

Tom Dagostino

Device Modeling Division

Teraspeed Consulting Group LLC

2926 SE Yamhill St.

Portland, OR 97214

(503) 430-1065

[email-masked]

http://www.teraspeed.com

  -----Original Message-----
  From: [email-masked]
[mailto:[email-masked]]On Behalf Of Abdulrahman A. Rafiq
  Sent: Friday, November 15, 2002 11:32 PM
  To: Eric Hsu; [email-masked]
  Subject: Re: [IBIS-Users] Question about warning message

  Eric,

  The warning message of "non-monotonic" is perfectly acceptable and can be
ignored. As for the warning message of extrreme currents present, it also is
acceptable. In fact if you open the .ibs file and comment our all the
extreme +ve and -ve currents in the I-V tables and then rerun ibischks, this
warning message will not show up.

  In short you needn't worry too much about these warnings.

  Hope this helps.

  Regards,

  Abdulrahman Rafiq

   Eric Hsu <[email-masked]> wrote:

    Hi All,

    When running ibischk3 to check ver2.1 model, if there are warning
    messages complaining about "non-monotonic"and "extreme currents present"
    around hundred amp level, is it possible and acceptible?

    Thanks

    ~eric

    |------------------------------------------------------------------
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    |with just the appropriate command message(s) in the body:
    |
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    | subscribe ibis
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    |
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  ************************************
  ABDULRAHMAN AK RAFIQ
  Scientific Engineering Consultants, Inc
  Phone: (805) 708-1976
  Email: [email-masked]
  URL: www.geocities.com/arafiqsi/
  ************************************

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<DIV><SPAN class=3D434591623-16112002><FONT face=3DArial color=3D#0000ff =
size=3D2>I'll=20
disagree on this.&nbsp; The extreme currents are likely OK but the =
non-monotonic=20
warnings may cause the simulations to not converge properly or in some=20
simulators cause the model not to load at all.&nbsp; If the sum of the =
IV curves=20
do not have monotonic issues you are OK.&nbsp; If the sum of the curves =
do have=20
monotonic issues I would investigate before I would say it is OK.&nbsp;=20
</FONT></SPAN></DIV>
<DIV>&nbsp;</DIV>
<DIV class=3DSection1>
<P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Tom Dagostino</SPAN></P>
<P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Device Modeling =
Division</SPAN></P>
<P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Teraspeed Consulting Group =

LLC</SPAN></P>
<P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">2926 SE Yamhill =
St.</SPAN></P>
<P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Portland, OR =
97214</SPAN></P>
<P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">(503) 430-1065</SPAN></P>
<P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Arial">[email-masked]</SPAN></P>
<P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Arial">http://www.teraspeed.com</SPAN></P></DIV>
<BLOCKQUOTE>
  <DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
  size=3D2>-----Original Message-----<BR><B>From:</B>=20
  [email-masked] =
[mailto:[email-masked]]<B>On=20
  Behalf Of </B>Abdulrahman A. Rafiq<BR><B>Sent:</B> Friday, November =
15, 2002=20
  11:32 PM<BR><B>To:</B> Eric Hsu; =
[email-masked]<BR><B>Subject:</B>=20
  Re: [IBIS-Users] Question about warning message<BR><BR></FONT></DIV>
  <P>Eric,=20
  <P>The warning message of "non-monotonic" is perfectly acceptable and =
can be=20
  ignored. As for the warning message of extrreme currents present, it =
also is=20
  acceptable. In fact if you open the .ibs file and comment our all the =
extreme=20
  +ve and -ve currents in the I-V tables and then rerun ibischks, this =
warning=20
  message will not show up.=20
  <P>In short you needn't worry too much about these warnings.=20
  <P>Hope this helps.=20
  <P>Regards,=20
  <P>Abdulrahman Rafiq=20
  <P>&nbsp;<B><I>Eric Hsu &lt;[email-masked]&gt;</I></B> wrote:=20
  <BLOCKQUOTE=20
  style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px =
solid">Hi=20
    All,<BR><BR>When running ibischk3 to check ver2.1 model, if there =
are=20
    warning<BR>messages complaining about "non-monotonic"and "extreme =
currents=20
    present"<BR>around hundred amp level, is it possible and=20
    =
acceptible?<BR><BR>Thanks<BR><BR>~eric<BR><BR>|--------------------------=
- ----------------------------------------<BR>|For=20
    help or to subscribe/unsubscribe, email [email-masked]<BR>|with =
just the=20
    appropriate command message(s) in the body:<BR>|<BR>| help<BR>| =
subscribe=20
    ibis <OPTIONAL e-mail address, if different><BR>| subscribe =
ibis-users=20
    <OPTIONAL e-mail address, if different><BR>| unsubscribe ibis =
<OPTIONAL=20
    e-mail address, if different><BR>| unsubscribe ibis-users <OPTIONAL =
e-mail=20
    address, if different><BR>|<BR>|or email a written request to=20
    [email-masked].<BR>|<BR>|IBIS reflector archives exist=20
    under:<BR>|<BR>| http://www.eda.org/pub/ibis/email_archive/ =
Recent<BR>|=20
    http://www.! eda.org/pub/ibis/users_archive/ Recent<BR>|=20
    http://www.eda.org/pub/ibis/email/ E-mail since=20
  =
1993</BLOCKQUOTE><BR><BR>************************************<BR>ABDULRAH=
MAN=20
  AK RAFIQ<BR>Scientific Engineering Consultants, Inc<BR>Phone: (805)=20
  708-1976<BR>Email: [email-masked] <BR>URL: =
www.geocities.com/arafiqsi/=20
  <BR>************************************
  <P><BR>
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href=3D"http://rd.yahoo.com/hosting/mailsig/*http://webhosting.yahoo.com"=
>Yahoo!=20
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site</BLOCKQUOTE></BODY></HTML>

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

Date: Mon, 18 Nov 2002 11:08:03 -0800
From: Kim Helliwell <[email-masked]>
Subject: Re: [IBIS-Users] Question about warning message

This is one of those areas where YMMV applies, I guess,
but I would say that most commercial simulators that handle
IBIS models are fairly good about filtering out non monotonic
behavior. At least, I've never had it be a problem. And it's
not clear how one is to combine the curves to check for
nonmonotoncity of the summed curves. I suppose that
pullup + powerclamp + groundclamp and pulldown + powerclamp
+ groundclamp would work, but during a transition, it's my
understanding that things are more complicated than that.

On the issue of extreme currents, I guess it depends on how
extreme. 100A would not give me heartburn, but I get really
nervous when we are talking about 10^14 or 10^25 amps.
While I suppose most simulators will take even these values
in stride, it always suggests a poor SPICE model used to create
the IBIS tables, which suggests sloppiness on the part of the
model maker. And that makes me wonder what else he/she
was careless about.

Kim

On Monday, November 18, 2002, at 10:27  AM, Angulo, John wrote:

> The following is posted on behalf of Tom Dagostino at Teraspeed 
> Consulting Group.  Please send any private replies to 
> [email-masked] only.
>
> ----------------------------------------------------------------
>
> I'll disagree on this.  The extreme currents are likely OK but the
> non-monotonic warnings may cause the simulations to not converge 
> properly or
> in some simulators cause the model not to load at all.  If the sum of 
> the IV
> curves do not have monotonic issues you are OK.  If the sum of the 
> curves do
> have monotonic issues I would investigate before I would say it is OK.
>
> Tom Dagostino
>
> Device Modeling Division
>
> Teraspeed Consulting Group LLC
>
> 2926 SE Yamhill St.
>
> Portland, OR 97214
>
> (503) 430-1065
>
> [email-masked]
>
> http://www.teraspeed.com
>
>   -----Original Message-----
>   From: [email-masked]
> [mailto:[email-masked]]On Behalf Of Abdulrahman A. 
> Rafiq
>   Sent: Friday, November 15, 2002 11:32 PM
>   To: Eric Hsu; [email-masked]
>   Subject: Re: [IBIS-Users] Question about warning message
>
>
>   Eric,
>
>   The warning message of "non-monotonic" is perfectly acceptable and 
> can be
> ignored. As for the warning message of extrreme currents present, it 
> also is
> acceptable. In fact if you open the .ibs file and comment our all the
> extreme +ve and -ve currents in the I-V tables and then rerun 
> ibischks, this
> warning message will not show up.
>
>   In short you needn't worry too much about these warnings.
>
>   Hope this helps.
>
>   Regards,
>
>   Abdulrahman Rafiq
>
Kim Helliwell
Apple Computer
[email-masked]
408 974 9936

|------------------------------------------------------------------
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|with just the appropriate command message(s) in the body:
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------------------------------

Date: Mon, 18 Nov 2002 09:06:59 -0800
From: "Beal, Weston" <[email-masked]>
Subject: RE: [IBIS-Users] Question about warning message

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Abdulrahman,
 
I don't agree with this statement.  Warning are indeed warnings and are there to inform you that you have a potential problem.  Simply ignoring warnings all the time can get you into trouble.  After discovering and evaluating what caused the warning then you might be justified in ignoring it.
 
The non-monotonic warning in ibischk is based on each I-V curve individually and that is not the thing that matters in simulation.  What you need to check is monotonicity of the sums of the curves (power clamp + ground clamp;  clamps + pullup;  clamps + pulldown).
 
The extreme currents warning might be acceptable, but only if the values are outside of the normal operating voltage range.  This is usually the case when the input clamp diodes are simulated in the conducting region and they have very little, or no resistance in the model.
 
Regards,
Weston Beal

- -----Original Message-----
From: Abdulrahman A. Rafiq [mailto:[email-masked]]
Sent: Friday, November 15, 2002 11:32 PM
To: Eric Hsu; [email-masked]
Subject: Re: [IBIS-Users] Question about warning message

Eric, 

The warning message of "non-monotonic" is perfectly acceptable and can be ignored. As for the warning message of extrreme currents present, it also is acceptable. In fact if you open the .ibs file and comment our all the extreme +ve and -ve currents in the I-V tables and then rerun ibischks, this warning message will not show up. 

In short you needn't worry too much about these warnings. 

Hope this helps. 

Regards, 

Abdulrahman Rafiq 

 Eric Hsu <[email-masked]> wrote: 

Hi All,

When running ibischk3 to check ver2.1 model, if there are warning
messages complaining about "non-monotonic"and "extreme currents present"
around hundred amp level, is it possible and acceptible?

Thanks

~eric

|------------------------------------------------------------------
|For help or to subscribe/unsubscribe, email [email-masked]
|with just the appropriate command message(s) in the body:
|
| help
| subscribe ibis 
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************************************
ABDULRAHMAN AK RAFIQ
Scientific Engineering Consultants, Inc
Phone: (805) 708-1976
Email: [email-masked] 
URL: www.geocities.com/arafiqsi/ 
************************************ 

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<BODY>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=498585716-18112002>Abdulrahman,</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=498585716-18112002></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=498585716-18112002>I 
don't agree with this statement.&nbsp; Warning are indeed warnings and are there 
to inform you that you have a potential problem.&nbsp; Simply ignoring warnings 
all the time can get you into trouble.&nbsp; After discovering and evaluating 
what caused the warning then you might be justified in ignoring 
it.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=498585716-18112002></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=498585716-18112002>The 
non-monotonic warning in ibischk is based on each I-V curve individually and 
that is not the thing that matters in simulation.&nbsp; What you need to check 
is monotonicity of the sums of the curves (power clamp + ground clamp;&nbsp; 
clamps + pullup;&nbsp; clamps + pulldown).</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=498585716-18112002></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=498585716-18112002>The 
extreme currents warning might be acceptable, but only if the values are outside 
of the normal operating voltage range.&nbsp; This is usually the case when the 
input clamp diodes are simulated in the conducting region and they have very 
little, or no resistance in the model.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=498585716-18112002></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=498585716-18112002>Regards,</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=498585716-18112002>Weston 
Beal</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=498585716-18112002></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN 
class=498585716-18112002></SPAN></FONT>&nbsp;</DIV>
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma 
size=2>-----Original Message-----<BR><B>From:</B> Abdulrahman A. Rafiq 
[mailto:[email-masked]]<BR><B>Sent:</B> Friday, November 15, 2002 11:32 
PM<BR><B>To:</B> Eric Hsu; [email-masked]<BR><B>Subject:</B> Re: 
[IBIS-Users] Question about warning message<BR><BR></FONT></DIV>
<P>Eric, 
<P>The warning message of "non-monotonic" is perfectly acceptable and can be 
ignored. As for the warning message of extrreme currents present, it also is 
acceptable. In fact if you open the .ibs file and comment our all the extreme 
+ve and -ve currents in the I-V tables and then rerun ibischks, this warning 
message will not show up. 
<P>In short you needn't worry too much about these warnings. 
<P>Hope this helps. 
<P>Regards, 
<P>Abdulrahman Rafiq 
<P>&nbsp;<B><I>Eric Hsu &lt;[email-masked]&gt;</I></B> wrote: 
<BLOCKQUOTE 
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">Hi 
  All,<BR><BR>When running ibischk3 to check ver2.1 model, if there are 
  warning<BR>messages complaining about "non-monotonic"and "extreme currents 
  present"<BR>around hundred amp level, is it possible and 
  acceptible?<BR><BR>Thanks<BR><BR>~eric<BR><BR>|------------------------------------------------------------------<BR>|For 
  help or to subscribe/unsubscribe, email [email-masked]<BR>|with just the 
  appropriate command message(s) in the body:<BR>|<BR>| help<BR>| subscribe ibis 
  <OPTIONAL e-mail address, if different><BR>| subscribe ibis-users <OPTIONAL 
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  if different><BR>| unsubscribe ibis-users <OPTIONAL e-mail address, if 
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  [email-masked].<BR>|<BR>|IBIS reflector archives exist under:<BR>|<BR>| 
  http://www.eda.org/pub/ibis/email_archive/ Recent<BR>| http://www.! 
  eda.org/pub/ibis/users_archive/ Recent<BR>| http://www.eda.org/pub/ibis/email/ 
  E-mail since 
1993</BLOCKQUOTE><BR><BR>************************************<BR>ABDULRAHMAN AK 
RAFIQ<BR>Scientific Engineering Consultants, Inc<BR>Phone: (805) 
708-1976<BR>Email: [email-masked] <BR>URL: www.geocities.com/arafiqsi/ 
<BR>************************************
<P><BR>
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------------------------------

Date: Mon, 18 Nov 2002 11:43:03 -0800
From: "Flora, Matthew" <[email-masked]>
Subject: RE: [IBIS-Users] Question about warning message

Hi All,

The non-monotonic warnings are generated by the IBIS Golden Parser because it is
not summing the I-V table together before checking for monotonicity.  I believe
there is a pending bug (71) fix to the IBIS Golden Parser which will sum the
tables before the monotonicity check.
http://www.vhdl.org/pub/ibis/bugs/ibischk/bug71

It has been argued that the extreme currents are acceptable because a part
pushed to those extremes may actually give extreme current in the instant before
it melts.  I believe this is because people are blindly following the -VCC to
2VCC voltage range recommendation for I-V tables and so are trying to come up
with currents well outside of the normal operating region for some parts.  I
don't know if the IBIS spec actually say it, but I believe the intention is that
the I-V tables should include all of the voltages where "interesting" things
happen.  If the part was never designed to handle voltages out at -VCC or 2VCC,
then the tables need not include such voltages.  I believe this was more common
when more people were doing bench measurements to make the tables and they
limited the voltage range to actual voltages that got close to melt down, but
not beyond.

Just my two pence,
Matthew Flora

> -----Original Message-----
> From: Angulo, John 
> Sent: Monday, November 18, 2002 10:28 AM
> To: [email-masked]'
> Subject: RE: [IBIS-Users] Question about warning message
> 
> 
> The following is posted on behalf of Tom Dagostino at 
> Teraspeed Consulting Group.  Please send any private replies 
> to [email-masked] only.
> 
> ----------------------------------------------------------------
> 
> I'll disagree on this.  The extreme currents are likely OK but the
> non-monotonic warnings may cause the simulations to not 
> converge properly or
> in some simulators cause the model not to load at all.  If 
> the sum of the IV
> curves do not have monotonic issues you are OK.  If the sum 
> of the curves do
> have monotonic issues I would investigate before I would say it is OK.
> 
> Tom Dagostino
> 
> Device Modeling Division
> 
> Teraspeed Consulting Group LLC
> 
> 2926 SE Yamhill St.
> 
> Portland, OR 97214
> 
> (503) 430-1065
> 
> [email-masked]
> 
> http://www.teraspeed.com
> 
>   -----Original Message-----
>   From: [email-masked]
> [mailto:[email-masked]]On Behalf Of 
> Abdulrahman A. Rafiq
>   Sent: Friday, November 15, 2002 11:32 PM
>   To: Eric Hsu; [email-masked]
>   Subject: Re: [IBIS-Users] Question about warning message
> 
> 
>   Eric,
> 
>   The warning message of "non-monotonic" is perfectly 
> acceptable and can be
> ignored. As for the warning message of extrreme currents 
> present, it also is
> acceptable. In fact if you open the .ibs file and comment our all the
> extreme +ve and -ve currents in the I-V tables and then rerun 
> ibischks, this
> warning message will not show up.
> 
>   In short you needn't worry too much about these warnings.
> 
>   Hope this helps.
> 
>   Regards,
> 
>   Abdulrahman Rafiq
> 
>    Eric Hsu <[email-masked]> wrote:
> 
>     Hi All,
> 
>     When running ibischk3 to check ver2.1 model, if there are warning
>     messages complaining about "non-monotonic"and "extreme 
> currents present"
>     around hundred amp level, is it possible and acceptible?
> 
>     Thanks
> 
>     ~eric
> 
>     
> |------------------------------------------------------------------
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>     |with just the appropriate command message(s) in the body:
>     |
>     | help
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> 
>   ************************************
>   ABDULRAHMAN AK RAFIQ
>   Scientific Engineering Consultants, Inc
>   Phone: (805) 708-1976
>   Email: [email-masked]
>   URL: www.geocities.com/arafiqsi/
>   ************************************
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> 
> 
> 
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> <DIV><SPAN class=3D434591623-16112002><FONT face=3DArial 
> color=3D#0000ff =
> size=3D2>I'll=20
> disagree on this.&nbsp; The extreme currents are likely OK but the =
> non-monotonic=20
> warnings may cause the simulations to not converge properly 
> or in some=20
> simulators cause the model not to load at all.&nbsp; If the 
> sum of the =
> IV curves=20
> do not have monotonic issues you are OK.&nbsp; If the sum of 
> the curves =
> do have=20
> monotonic issues I would investigate before I would say it is 
> OK.&nbsp;=20
> </FONT></SPAN></DIV>
> <DIV>&nbsp;</DIV>
> <DIV class=3DSection1>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Tom Dagostino</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Device Modeling =
> Division</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Teraspeed 
> Consulting Group =
> 
> LLC</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">2926 SE Yamhill =
> St.</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Portland, OR =
> 97214</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">(503) 
> 430-1065</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
> Arial">[email-masked]</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
> Arial">http://www.teraspeed.com</SPAN></P></DIV>
> <BLOCKQUOTE>
>   <DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
> face=3DTahoma=20
>   size=3D2>-----Original Message-----<BR><B>From:</B>=20
>   [email-masked] =
> [mailto:[email-masked]]<B>On=20
>   Behalf Of </B>Abdulrahman A. Rafiq<BR><B>Sent:</B> Friday, 
> November =
> 15, 2002=20
>   11:32 PM<BR><B>To:</B> Eric Hsu; =
> [email-masked]<BR><B>Subject:</B>=20
>   Re: [IBIS-Users] Question about warning message<BR><BR></FONT></DIV>
>   <P>Eric,=20
>   <P>The warning message of "non-monotonic" is perfectly 
> acceptable and =
> can be=20
>   ignored. As for the warning message of extrreme currents 
> present, it =
> also is=20
>   acceptable. In fact if you open the .ibs file and comment 
> our all the =
> extreme=20
>   +ve and -ve currents in the I-V tables and then rerun 
> ibischks, this =
> warning=20
>   message will not show up.=20
>   <P>In short you needn't worry too much about these warnings.=20
>   <P>Hope this helps.=20
>   <P>Regards,=20
>   <P>Abdulrahman Rafiq=20
>   <P>&nbsp;<B><I>Eric Hsu 
> &lt;[email-masked]&gt;</I></B> wrote:=20
>   <BLOCKQUOTE=20
>   style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: 
> #1010ff 2px =
> solid">Hi=20
>     All,<BR><BR>When running ibischk3 to check ver2.1 model, 
> if there =
> are=20
>     warning<BR>messages complaining about "non-monotonic"and 
> "extreme =
> currents=20
>     present"<BR>around hundred amp level, is it possible and=20
>     =
> acceptible?<BR><BR>Thanks<BR><BR>~eric<BR><BR>|---------------
> -----------=
> ----------------------------------------<BR>|For=20
>     help or to subscribe/unsubscribe, email 
> [email-masked]<BR>|with =
> just the=20
>     appropriate command message(s) in the body:<BR>|<BR>| help<BR>| =
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>   =
> 1993</BLOCKQUOTE><BR><BR>************************************<
> BR>ABDULRAH=
> MAN=20
>   AK RAFIQ<BR>Scientific Engineering Consultants, 
> Inc<BR>Phone: (805)=20
>   708-1976<BR>Email: [email-masked] <BR>URL: =
> www.geocities.com/arafiqsi/=20
>   <BR>************************************
>   <P><BR>
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> 
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------------------------------

Date: Mon, 18 Nov 2002 13:08:58 -0800
From: Fred Balistreri <[email-masked]>
Subject: Re: [IBIS-Users] Question about warning message

The reason IBIS models go from -Vcc to 2Vcc is because that is what it
says in the spec. The following is a direct quote from the spec,
immediately
following the section that describes the testing voltage range:

"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."

If we don't want people to follow the spec then I would argue that the
spec needs modification. More importantly because of the spec ibis tools
all
conform to the voltage testing as prescribed, included s2ibis which a
lot
of people use. So I don't think the statement about people blindly
following
the voltage requirement is true. It may be more of the case that
historically
this is what we have done, which can be traced back to where it all
started,
the specification itself.

Best Regards,

"Flora, Matthew" wrote:
> 
> Hi All,
> 
> The non-monotonic warnings are generated by the IBIS Golden Parser because it is
> not summing the I-V table together before checking for monotonicity.  I believe
> there is a pending bug (71) fix to the IBIS Golden Parser which will sum the
> tables before the monotonicity check.
> http://www.vhdl.org/pub/ibis/bugs/ibischk/bug71
> 
> It has been argued that the extreme currents are acceptable because a part
> pushed to those extremes may actually give extreme current in the instant before
> it melts.  I believe this is because people are blindly following the -VCC to
> 2VCC voltage range recommendation for I-V tables and so are trying to come up
> with currents well outside of the normal operating region for some parts.  I
> don't know if the IBIS spec actually say it, but I believe the intention is that
> the I-V tables should include all of the voltages where "interesting" things
> happen.  If the part was never designed to handle voltages out at -VCC or 2VCC,
> then the tables need not include such voltages.  I believe this was more common
> when more people were doing bench measurements to make the tables and they
> limited the voltage range to actual voltages that got close to melt down, but
> not beyond.
> 
> Just my two pence,
> Matthew Flora
> 
> > -----Original Message-----
> > From: Angulo, John
> > Sent: Monday, November 18, 2002 10:28 AM
> > To: [email-masked]'
> > Subject: RE: [IBIS-Users] Question about warning message
> >
> >
> > The following is posted on behalf of Tom Dagostino at
> > Teraspeed Consulting Group.  Please send any private replies
> > to [email-masked] only.
> >
> > ----------------------------------------------------------------
> >
> > I'll disagree on this.  The extreme currents are likely OK but the
> > non-monotonic warnings may cause the simulations to not
> > converge properly or
> > in some simulators cause the model not to load at all.  If
> > the sum of the IV
> > curves do not have monotonic issues you are OK.  If the sum
> > of the curves do
> > have monotonic issues I would investigate before I would say it is OK.
> >
> > Tom Dagostino
> >
> > Device Modeling Division
> >
> > Teraspeed Consulting Group LLC
> >
> > 2926 SE Yamhill St.
> >
> > Portland, OR 97214
> >
> > (503) 430-1065
> >
> > [email-masked]
> >
> > http://www.teraspeed.com
> >
> >   -----Original Message-----
> >   From: [email-masked]
> > [mailto:[email-masked]]On Behalf Of
> > Abdulrahman A. Rafiq
> >   Sent: Friday, November 15, 2002 11:32 PM
> >   To: Eric Hsu; [email-masked]
> >   Subject: Re: [IBIS-Users] Question about warning message
> >
> >
> >   Eric,
> >
> >   The warning message of "non-monotonic" is perfectly
> > acceptable and can be
> > ignored. As for the warning message of extrreme currents
> > present, it also is
> > acceptable. In fact if you open the .ibs file and comment our all the
> > extreme +ve and -ve currents in the I-V tables and then rerun
> > ibischks, this
> > warning message will not show up.
> >
> >   In short you needn't worry too much about these warnings.
> >
> >   Hope this helps.
> >
> >   Regards,
> >
> >   Abdulrahman Rafiq
> >
> >    Eric Hsu <[email-masked]> wrote:
> >
> >     Hi All,
> >
> >     When running ibischk3 to check ver2.1 model, if there are warning
> >     messages complaining about "non-monotonic"and "extreme
> > currents present"
> >     around hundred amp level, is it possible and acceptible?
> >
> >     Thanks
> >
> >     ~eric
> >
> >
> > |------------------------------------------------------------------
> >     |For help or to subscribe/unsubscribe, email [email-masked]
> >     |with just the appropriate command message(s) in the body:
> >     |
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> >     |
> >     | 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
> >
> >
> >   ************************************
> >   ABDULRAHMAN AK RAFIQ
> >   Scientific Engineering Consultants, Inc
> >   Phone: (805) 708-1976
> >   Email: [email-masked]
> >   URL: www.geocities.com/arafiqsi/
> >   ************************************
> >
> >
> >
> >
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> > <BODY>
> > <DIV><SPAN class=3D434591623-16112002><FONT face=3DArial
> > color=3D#0000ff =
> > size=3D2>I'll=20
> > disagree on this.&nbsp; The extreme currents are likely OK but the =
> > non-monotonic=20
> > warnings may cause the simulations to not converge properly
> > or in some=20
> > simulators cause the model not to load at all.&nbsp; If the
> > sum of the =
> > IV curves=20
> > do not have monotonic issues you are OK.&nbsp; If the sum of
> > the curves =
> > do have=20
> > monotonic issues I would investigate before I would say it is
> > OK.&nbsp;=20
> > </FONT></SPAN></DIV>
> > <DIV>&nbsp;</DIV>
> > <DIV class=3DSection1>
> > <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> > style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Tom Dagostino</SPAN></P>
> > <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> > style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Device Modeling =
> > Division</SPAN></P>
> > <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> > style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Teraspeed
> > Consulting Group =
> >
> > LLC</SPAN></P>
> > <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> > style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">2926 SE Yamhill =
> > St.</SPAN></P>
> > <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> > style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Portland, OR =
> > 97214</SPAN></P>
> > <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> > style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">(503)
> > 430-1065</SPAN></P>
> > <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> > style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
> > Arial">[email-masked]</SPAN></P>
> > <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> > style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
> > Arial">http://www.teraspeed.com</SPAN></P></DIV>
> > <BLOCKQUOTE>
> >   <DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
> > face=3DTahoma=20
> >   size=3D2>-----Original Message-----<BR><B>From:</B>=20
> >   [email-masked] =
> > [mailto:[email-masked]]<B>On=20
> >   Behalf Of </B>Abdulrahman A. Rafiq<BR><B>Sent:</B> Friday,
> > November =
> > 15, 2002=20
> >   11:32 PM<BR><B>To:</B> Eric Hsu; =
> > [email-masked]<BR><B>Subject:</B>=20
> >   Re: [IBIS-Users] Question about warning message<BR><BR></FONT></DIV>
> >   <P>Eric,=20
> >   <P>The warning message of "non-monotonic" is perfectly
> > acceptable and =
> > can be=20
> >   ignored. As for the warning message of extrreme currents
> > present, it =
> > also is=20
> >   acceptable. In fact if you open the .ibs file and comment
> > our all the =
> > extreme=20
> >   +ve and -ve currents in the I-V tables and then rerun
> > ibischks, this =
> > warning=20
> >   message will not show up.=20
> >   <P>In short you needn't worry too much about these warnings.=20
> >   <P>Hope this helps.=20
> >   <P>Regards,=20
> >   <P>Abdulrahman Rafiq=20
> >   <P>&nbsp;<B><I>Eric Hsu
> > &lt;[email-masked]&gt;</I></B> wrote:=20
> >   <BLOCKQUOTE=20
> >   style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT:
> > #1010ff 2px =
> > solid">Hi=20
> >     All,<BR><BR>When running ibischk3 to check ver2.1 model,
> > if there =
> > are=20
> >     warning<BR>messages complaining about "non-monotonic"and
> > "extreme =
> > currents=20
> >     present"<BR>around hundred amp level, is it possible and=20
> >     =
> > acceptible?<BR><BR>Thanks<BR><BR>~eric<BR><BR>|---------------
> > -----------=
> > ----------------------------------------<BR>|For=20
> >     help or to subscribe/unsubscribe, email
> > [email-masked]<BR>|with =
> > just the=20
> >     appropriate command message(s) in the body:<BR>|<BR>| help<BR>| =
> > subscribe=20
> >     ibis <OPTIONAL e-mail address, if different><BR>| subscribe =
> > ibis-users=20
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> > <OPTIONAL=20
> >     e-mail address, if different><BR>| unsubscribe ibis-users
> > <OPTIONAL =
> > e-mail=20
> >     address, if different><BR>|<BR>|or email a written request to=20
> >     [email-masked].<BR>|<BR>|IBIS reflector archives exist=20
> >     under:<BR>|<BR>| http://www.eda.org/pub/ibis/email_archive/ =
> > Recent<BR>|=20
> >     http://www.! eda.org/pub/ibis/users_archive/ Recent<BR>|=20
> >     http://www.eda.org/pub/ibis/email/ E-mail since=20
> >   =
> > 1993</BLOCKQUOTE><BR><BR>************************************<
> > BR>ABDULRAH=
> > MAN=20
> >   AK RAFIQ<BR>Scientific Engineering Consultants,
> > Inc<BR>Phone: (805)=20
> >   708-1976<BR>Email: [email-masked] <BR>URL: =
> > www.geocities.com/arafiqsi/=20
> >   <BR>************************************
> >   <P><BR>
> >   <HR SIZE=3D1>
> >   Do you Yahoo!?<BR><A=20
> >   =
> > href=3D"http://rd.yahoo.com/hosting/mailsig/*http://webhosting
> > .yahoo.com"=
> > >Yahoo!=20
> >   Web Hosting</A> - Let the expert host your =
> > site</BLOCKQUOTE></BODY></HTML>
> >
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> > |  http://www.eda.org/pub/ibis/email/          E-mail since 1993
> >
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- -- 
Fred Balistreri
[email-masked]

http://www.apsimtech.com
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------------------------------

Date: Mon, 18 Nov 2002 13:30:47 -0800
From: "Flora, Matthew" <[email-masked]>
Subject: RE: [IBIS-Users] Question about warning message

Dear Fred,

My apologies.  I didn't remember the spec saying "must".  I thought it said "should".  My mistake.

Cheers,
Matthew Flora

> -----Original Message-----
> From: Fred Balistreri [mailto:[email-masked]]
> Sent: Monday, November 18, 2002 1:09 PM
> To: Flora, Matthew
> Cc: [email-masked]'
> Subject: Re: [IBIS-Users] Question about warning message
> 
> 
> The reason IBIS models go from -Vcc to 2Vcc is because that is what it
> says in the spec. The following is a direct quote from the spec,
> immediately
> following the section that describes the testing voltage range:
> 
> "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."
> 
> If we don't want people to follow the spec then I would argue that the
> spec needs modification. More importantly because of the spec 
> ibis tools
> all
> conform to the voltage testing as prescribed, included s2ibis which a
> lot
> of people use. So I don't think the statement about people blindly
> following
> the voltage requirement is true. It may be more of the case that
> historically
> this is what we have done, which can be traced back to where it all
> started,
> the specification itself.
> 
> Best Regards,
> 
> "Flora, Matthew" wrote:
> > 
> > Hi All,
> > 
> > The non-monotonic warnings are generated by the IBIS Golden 
> Parser because it is
> > not summing the I-V table together before checking for 
> monotonicity.  I believe
> > there is a pending bug (71) fix to the IBIS Golden Parser 
> which will sum the
> > tables before the monotonicity check.
> > http://www.vhdl.org/pub/ibis/bugs/ibischk/bug71
> > 
> > It has been argued that the extreme currents are acceptable 
> because a part
> > pushed to those extremes may actually give extreme current 
> in the instant before
> > it melts.  I believe this is because people are blindly 
> following the -VCC to
> > 2VCC voltage range recommendation for I-V tables and so are 
> trying to come up
> > with currents well outside of the normal operating region 
> for some parts.  I
> > don't know if the IBIS spec actually say it, but I believe 
> the intention is that
> > the I-V tables should include all of the voltages where 
> "interesting" things
> > happen.  If the part was never designed to handle voltages 
> out at -VCC or 2VCC,
> > then the tables need not include such voltages.  I believe 
> this was more common
> > when more people were doing bench measurements to make the 
> tables and they
> > limited the voltage range to actual voltages that got close 
> to melt down, but
> > not beyond.
> > 
> > Just my two pence,
> > Matthew Flora
> 
> -- 
> Fred Balistreri
> [email-masked]
> 
> http://www.apsimtech.com
> 
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------------------------------

Date: Mon, 18 Nov 2002 13:55:04 -0800
From: "Muranyi, Arpad" <[email-masked]>
Subject: RE: [IBIS-Users] Question about warning message

The problem is that this part of the spec is very old, it was
written in IBIS 1.1.  In those days we used mostly unterminated
busses, and most buffers switched rail to rail.  Given that
it was simple to say we need to cover -Vcc to 2*Vcc with the
IV tables.

However, this is not true any more.  Most of our buffers are
small signal swing, most of our signals are parallel terminated,
etc...  Consider the example of a 3.3V GTL buffer.  The signal
goes from about 0.5V to 1.5V, a 1V swing.  Even if it was
unterminated, the signal would only be driven from 0 to 1.5V.
Adding the effects of FULL reflection, the doubling would
give us a theoretical maximum swing of -1.5 to 3.0V.  However,
according to the spec, because the power supply to the buffer
is 3.3V, the range "must" be -3.3V to 6.6V.  For this signal,
which couldn't possibly go beyond -1.5V to 3.0V it doesn't
make sense to require a table that covers -3.3V to 6.6V.
So the IBIS specification should be changed, in my opinion,
or this rule needs to be handled with a grain of salt...

Please note, I am not signing up for writing a BIRD...

Arpad Muranyi
Itel Corporation
================================================================

- -----Original Message-----
From: Flora, Matthew [mailto:[email-masked]]
Sent: Monday, November 18, 2002 1:31 PM
To: Fred Balistreri
Cc: [email-masked]'
Subject: RE: [IBIS-Users] Question about warning message

Dear Fred,

My apologies.  I didn't remember the spec saying "must".  I thought it said "should".  My mistake.

Cheers,
Matthew Flora

> -----Original Message-----
> From: Fred Balistreri [mailto:[email-masked]]
> Sent: Monday, November 18, 2002 1:09 PM
> To: Flora, Matthew
> Cc: [email-masked]'
> Subject: Re: [IBIS-Users] Question about warning message
> 
> 
> The reason IBIS models go from -Vcc to 2Vcc is because that is what it
> says in the spec. The following is a direct quote from the spec,
> immediately
> following the section that describes the testing voltage range:
> 
> "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."
> 
> If we don't want people to follow the spec then I would argue that the
> spec needs modification. More importantly because of the spec 
> ibis tools
> all
> conform to the voltage testing as prescribed, included s2ibis which a
> lot
> of people use. So I don't think the statement about people blindly
> following
> the voltage requirement is true. It may be more of the case that
> historically
> this is what we have done, which can be traced back to where it all
> started,
> the specification itself.
> 
> Best Regards,
> Fred Balistreri
> [email-masked]
> 
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------------------------------

Date: Mon, 18 Nov 2002 18:31:58 -0500
From: "Ingraham, Andrew" <[email-masked]>
Subject: RE: [IBIS-Users] Question about warning message

Maybe I'm the only person who feels this way, but in my opinion, there's
nothing wrong with a *table* that goes from -Vcc to +2Vcc.

But I agree that in many (if not most) cases it doesn't make sense to
force someone to measure currents over the full range, if they become
unreasonably large.  Nor to extract such currents from SPICE using
s2ibis*.

In my opinion, the specification ought to make clear what to do in those
circumstances.  Maybe what it needs, are additional comments about how
to create a full table when data points cannot be measured because the
chip would melt, or what to do when the simulated currents from SPICE
get unwieldy.

Some modern devices really need to have tables that go from -Vcc to
+2Vcc.  There are some ICs that switch rail-to-rail and also lack one or
both clamping diodes, or that have clamp diodes that are so weak that
one could easily go a few volts into clamping without breaking a sweat.

Rather than letting model creators choose to use a narrower range, and
risk having too little data, I would rather force the model creators to
think about what they're doing, and come up with "best data" over the
full range even if some of it *might* not be used because the voltages
"never" go there.  Anytime you say "never", someone could come up with a
case that contradicts your assumptions.

Regards,
Andy

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

Date: Mon, 18 Nov 2002 22:31:12 -0800
From: "Scott McMorrow" <[email-masked]>
Subject: Re: [IBIS-Users] Question about warning message]

- --------------070709020909020406070609
Content-Type: text/plain; charset=ISO-8859-15; format=flowed
Content-Transfer-Encoding: 7bit

   Fred,

Damn!  You actually read the spec and are absolutely correct.  This is 
something that really needs to be corrected, as it it quite 
inappropriate for modern devices.

regards,

scott

\

- -- 
Scott McMorrow
Teraspeed Consulting Group LLC
2926 SE Yamhill St.
Portland, OR 97214
(503) 239-5536
http://www.teraspeed.com

Fred Balistreri wrote:

>The reason IBIS models go from -Vcc to 2Vcc is because that is what it
>says in the spec. The following is a direct quote from the spec,
>immediately
>following the section that describes the testing voltage range:
>
>"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."
>
>If we don't want people to follow the spec then I would argue that the
>spec needs modification. More importantly because of the spec ibis tools
>all
>conform to the voltage testing as prescribed, included s2ibis which a
>lot
>of people use. So I don't think the statement about people blindly
>following
>the voltage requirement is true. It may be more of the case that
>historically
>this is what we have done, which can be traced back to where it all
>started,
>the specification itself.
>
>Best Regards,
>
>"Flora, Matthew" wrote:
>  
>
>>Hi All,
>>
>>The non-monotonic warnings are generated by the IBIS Golden Parser because it is
>>not summing the I-V table together before checking for monotonicity.  I believe
>>there is a pending bug (71) fix to the IBIS Golden Parser which will sum the
>>tables before the monotonicity check.
>>http://www.vhdl.org/pub/ibis/bugs/ibischk/bug71
>>
>>It has been argued that the extreme currents are acceptable because a part
>>pushed to those extremes may actually give extreme current in the instant before
>>it melts.  I believe this is because people are blindly following the -VCC to
>>2VCC voltage range recommendation for I-V tables and so are trying to come up
>>with currents well outside of the normal operating region for some parts.  I
>>don't know if the IBIS spec actually say it, but I believe the intention is that
>>the I-V tables should include all of the voltages where "interesting" things
>>happen.  If the part was never designed to handle voltages out at -VCC or 2VCC,
>>then the tables need not include such voltages.  I believe this was more common
>>when more people were doing bench measurements to make the tables and they
>>limited the voltage range to actual voltages that got close to melt down, but
>>not beyond.
>>
>>Just my two pence,
>>Matthew Flora
>>
>>    
>>
>>>-----Original Message-----
>>>From: Angulo, John
>>>Sent: Monday, November 18, 2002 10:28 AM
>>>To: [email-masked]'
>>>Subject: RE: [IBIS-Users] Question about warning message
>>>
>>>
>>>The following is posted on behalf of Tom Dagostino at
>>>Teraspeed Consulting Group.  Please send any private replies
>>>to [email-masked] only.
>>>
>>>----------------------------------------------------------------
>>>
>>>I'll disagree on this.  The extreme currents are likely OK but the
>>>non-monotonic warnings may cause the simulations to not
>>>converge properly or
>>>in some simulators cause the model not to load at all.  If
>>>the sum of the IV
>>>curves do not have monotonic issues you are OK.  If the sum
>>>of the curves do
>>>have monotonic issues I would investigate before I would say it is OK.
>>>
>>>Tom Dagostino
>>>
>>>Device Modeling Division
>>>
>>>Teraspeed Consulting Group LLC
>>>
>>>2926 SE Yamhill St.
>>>
>>>Portland, OR 97214
>>>
>>>(503) 430-1065
>>>
>>>[email-masked]
>>>
>>>http://www.teraspeed.com
>>>
>>>  -----Original Message-----
>>>  From: [email-masked]
>>>[mailto:[email-masked]]On Behalf Of
>>>Abdulrahman A. Rafiq
>>>  Sent: Friday, November 15, 2002 11:32 PM
>>>  To: Eric Hsu; [email-masked]
>>>  Subject: Re: [IBIS-Users] Question about warning message
>>>
>>>
>>>  Eric,
>>>
>>>  The warning message of "non-monotonic" is perfectly
>>>acceptable and can be
>>>ignored. As for the warning message of extrreme currents
>>>present, it also is
>>>acceptable. In fact if you open the .ibs file and comment our all the
>>>extreme +ve and -ve currents in the I-V tables and then rerun
>>>ibischks, this
>>>warning message will not show up.
>>>
>>>  In short you needn't worry too much about these warnings.
>>>
>>>  Hope this helps.
>>>
>>>  Regards,
>>>
>>>  Abdulrahman Rafiq
>>>
>>>   Eric Hsu <[email-masked]> wrote:
>>>
>>>    Hi All,
>>>
>>>    When running ibischk3 to check ver2.1 model, if there are warning
>>>    messages complaining about "non-monotonic"and "extreme
>>>currents present"
>>>    around hundred amp level, is it possible and acceptible?
>>>
>>>    Thanks
>>>
>>>    ~eric
>>>
>>>
>>>|------------------------------------------------------------------
>>>    |For help or to subscribe/unsubscribe, email [email-masked]
>>>    |with just the appropriate command message(s) in the body:
>>>    |
>>>    | help
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>>>    |
>>>    |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
>>>
>>>
>>>  ************************************
>>>  ABDULRAHMAN AK RAFIQ
>>>  Scientific Engineering Consultants, Inc
>>>  Phone: (805) 708-1976
>>>  Email: [email-masked]
>>>  URL: www.geocities.com/arafiqsi/
>>>  ************************************
>>>
>>>
>>>
>>>
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>>>--------------
>>>--
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>>>  Yahoo! Web Hosting - Let the expert host your site
>>>
>>>------=_NextPart_000_008A_01C28D83.9D8DBFE0
>>>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=3D"Content-Type" CONTENT=3D"text/html; =
>>>charset=3Dus-ascii">
>>>
>>>
>>><META content=3D"MSHTML 5.50.4916.2300" name=3DGENERATOR></HEAD>
>>><BODY>
>>><DIV><SPAN class=3D434591623-16112002><FONT face=3DArial
>>>color=3D#0000ff =
>>>size=3D2>I'll=20
>>>disagree on this.&nbsp; The extreme currents are likely OK but the =
>>>non-monotonic=20
>>>warnings may cause the simulations to not converge properly
>>>or in some=20
>>>simulators cause the model not to load at all.&nbsp; If the
>>>sum of the =
>>>IV curves=20
>>>do not have monotonic issues you are OK.&nbsp; If the sum of
>>>the curves =
>>>do have=20
>>>monotonic issues I would investigate before I would say it is
>>>OK.&nbsp;=20
>>></FONT></SPAN></DIV>
>>><DIV>&nbsp;</DIV>
>>><DIV class=3DSection1>
>>><P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
>>>style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Tom Dagostino</SPAN></P>
>>><P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
>>>style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Device Modeling =
>>>Division</SPAN></P>
>>><P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
>>>style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Teraspeed
>>>Consulting Group =
>>>
>>>LLC</SPAN></P>
>>><P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
>>>style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">2926 SE Yamhill =
>>>St.</SPAN></P>
>>><P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
>>>style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Portland, OR =
>>>97214</SPAN></P>
>>><P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
>>>style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">(503)
>>>430-1065</SPAN></P>
>>><P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
>>>style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
>>>Arial">[email-masked]</SPAN></P>
>>><P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
>>>style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
>>>Arial">http://www.teraspeed.com</SPAN></P></DIV>
>>><BLOCKQUOTE>
>>>  <DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
>>>face=3DTahoma=20
>>>  size=3D2>-----Original Message-----<BR><B>From:</B>=20
>>>  [email-masked] =
>>>[mailto:[email-masked]]<B>On=20
>>>  Behalf Of </B>Abdulrahman A. Rafiq<BR><B>Sent:</B> Friday,
>>>November =
>>>15, 2002=20
>>>  11:32 PM<BR><B>To:</B> Eric Hsu; =
>>>[email-masked]<BR><B>Subject:</B>=20
>>>  Re: [IBIS-Users] Question about warning message<BR><BR></FONT></DIV>
>>>  <P>Eric,=20
>>>  <P>The warning message of "non-monotonic" is perfectly
>>>acceptable and =
>>>can be=20
>>>  ignored. As for the warning message of extrreme currents
>>>present, it =
>>>also is=20
>>>  acceptable. In fact if you open the .ibs file and comment
>>>our all the =
>>>extreme=20
>>>  +ve and -ve currents in the I-V tables and then rerun
>>>ibischks, this =
>>>warning=20
>>>  message will not show up.=20
>>>  <P>In short you needn't worry too much about these warnings.=20
>>>  <P>Hope this helps.=20
>>>  <P>Regards,=20
>>>  <P>Abdulrahman Rafiq=20
>>>  <P>&nbsp;<B><I>Eric Hsu
>>>&lt;[email-masked]&gt;</I></B> wrote:=20
>>>  <BLOCKQUOTE=20
>>>  style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT:
>>>#1010ff 2px =
>>>solid">Hi=20
>>>    All,<BR><BR>When running ibischk3 to check ver2.1 model,
>>>if there =
>>>are=20
>>>    warning<BR>messages complaining about "non-monotonic"and
>>>"extreme =
>>>currents=20
>>>    present"<BR>around hundred amp level, is it possible and=20
>>>    =
>>>acceptible?<BR><BR>Thanks<BR><BR>~eric<BR><BR>|---------------
>>>-----------=
>>>----------------------------------------<BR>|For=20
>>>    help or to subscribe/unsubscribe, email
>>>[email-masked]<BR>|with =
>>>just the=20
>>>    appropriate command message(s) in the body:<BR>|<BR>| help<BR>| =
>>>subscribe=20
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>>>ibis-users=20
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>>><OPTIONAL=20
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>>><OPTIONAL =
>>>e-mail=20
>>>    address, if different><BR>|<BR>|or email a written request to=20
>>>    [email-masked].<BR>|<BR>|IBIS reflector archives exist=20
>>>    under:<BR>|<BR>| http://www.eda.org/pub/ibis/email_archive/ =
>>>Recent<BR>|=20
>>>    http://www.! eda.org/pub/ibis/users_archive/ Recent<BR>|=20
>>>    http://www.eda.org/pub/ibis/email/ E-mail since=20
>>>  =
>>>1993</BLOCKQUOTE><BR><BR>************************************<
>>>BR>ABDULRAH=
>>>MAN=20
>>>  AK RAFIQ<BR>Scientific Engineering Consultants,
>>>Inc<BR>Phone: (805)=20
>>>  708-1976<BR>Email: [email-masked] <BR>URL: =
>>>www.geocities.com/arafiqsi/=20
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>>>  Do you Yahoo!?<BR><A=20
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>>>  Web Hosting</A> - Let the expert host your =
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>>>
>>>      
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>>    
>>
>
>  
>

- -- 
Scott McMorrow
Teraspeed Consulting Group LLC
2926 SE Yamhill St.
Portland, OR 97214
(503) 239-5536
http://www.teraspeed.com

- --------------070709020909020406070609
Content-Type: text/html; charset=ISO-8859-15
Content-Transfer-Encoding: 8bit

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<meta http-equiv="Content-Type" content="text/html;charset=ISO-8859-15">
<title></title>
         Fred,<br>
 <br>
 Damn!  You actually read the spec and are absolutely correct.  This is something 
that really needs to be corrected, as it it quite inappropriate for modern 
devices.<br>
 <br>
 regards,<br>
 <br>
 scott<br>
 <br>
 \ 
<pre class="moz-signature" cols="$mailwrapcol">-- 
Scott McMorrow
Teraspeed Consulting Group LLC
2926 SE Yamhill St.
Portland, OR 97214
(503) 239-5536
<a class="moz-txt-link-freetext" href="http://www.teraspeed.com">http://www.teraspeed.com</a>

</pre>
 <br>
 <br>
 Fred Balistreri wrote:<br>
 
<blockquote type="cite" cite="[email-masked]">   
  <pre wrap="">The reason IBIS models go from -Vcc to 2Vcc is because that is what it
says in the spec. The following is a direct quote from the spec,
immediately
following the section that describes the testing voltage range:

"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."

If we don't want people to follow the spec then I would argue that the
spec needs modification. More importantly because of the spec ibis tools
all
conform to the voltage testing as prescribed, included s2ibis which a
lot
of people use. So I don't think the statement about people blindly
following
the voltage requirement is true. It may be more of the case that
historically
this is what we have done, which can be traced back to where it all
started,
the specification itself.

Best Regards,

"Flora, Matthew" wrote:
  </pre>
   
  <blockquote type="cite">     
    <pre wrap="">Hi All,

The non-monotonic warnings are generated by the IBIS Golden Parser because it is
not summing the I-V table together before checking for monotonicity.  I believe
there is a pending bug (71) fix to the IBIS Golden Parser which will sum the
tables before the monotonicity check.
<a class="moz-txt-link-freetext"
 href="http://www.vhdl.org/pub/ibis/bugs/ibischk/bug71">http://www.vhdl.org/pub/ibis/bugs/ibischk/bug71</a>

It has been argued that the extreme currents are acceptable because a part
pushed to those extremes may actually give extreme current in the instant before
it melts.  I believe this is because people are blindly following the -VCC to
2VCC voltage range recommendation for I-V tables and so are trying to come up
with currents well outside of the normal operating region for some parts.  I
don't know if the IBIS spec actually say it, but I believe the intention is that
the I-V tables should include all of the voltages where "interesting" things
happen.  If the part was never designed to handle voltages out at -VCC or 2VCC,
then the tables need not include such voltages.  I believe this was more common
when more people were doing bench measurements to make the tables and they
limited the voltage range to actual voltages that got close to melt down, but
not beyond.

Just my two pence,
Matthew Flora

    </pre>
     
    <blockquote type="cite">       
      <pre wrap="">-----Original Message-----
From: Angulo, John
Sent: Monday, November 18, 2002 10:28 AM
To: '<a
 class="moz-txt-link-abbreviated" href="mailto:[email-masked]">[email-masked]</a>'
Subject: RE: [IBIS-Users] Question about warning message

The following is posted on behalf of Tom Dagostino at
Teraspeed Consulting Group.  Please send any private replies
to <a
 class="moz-txt-link-abbreviated" href="mailto:[email-masked]">[email-masked]</a> only.

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

I'll disagree on this.  The extreme currents are likely OK but the
non-monotonic warnings may cause the simulations to not
converge properly or
in some simulators cause the model not to load at all.  If
the sum of the IV
curves do not have monotonic issues you are OK.  If the sum
of the curves do
have monotonic issues I would investigate before I would say it is OK.

Tom Dagostino

Device Modeling Division

Teraspeed Consulting Group LLC

2926 SE Yamhill St.

Portland, OR 97214

(503) 430-1065

<a class="moz-txt-link-abbreviated" href="mailto:[email-masked]">[email-masked]</a>

<a class="moz-txt-link-freetext" href="http://www.teraspeed.com">http://www.teraspeed.com</a>

  -----Original Message-----
  From: <a
 class="moz-txt-link-abbreviated"
 href="mailto:[email-masked]">[email-masked]</a>
[<a
 class="moz-txt-link-freetext"
 href="mailto:[email-masked]">mailto:[email-masked]</a>]On Behalf Of
Abdulrahman A. Rafiq
  Sent: Friday, November 15, 2002 11:32 PM
  To: Eric Hsu; <a
 class="moz-txt-link-abbreviated"
 href="mailto:[email-masked]">[email-masked]</a>
  Subject: Re: [IBIS-Users] Question about warning message

  Eric,

  The warning message of "non-monotonic" is perfectly
acceptable and can be
ignored. As for the warning message of extrreme currents
present, it also is
acceptable. In fact if you open the .ibs file and comment our all the
extreme +ve and -ve currents in the I-V tables and then rerun
ibischks, this
warning message will not show up.

  In short you needn't worry too much about these warnings.

  Hope this helps.

  Regards,

  Abdulrahman Rafiq

   Eric Hsu <a
 class="moz-txt-link-rfc2396E" href="mailto:[email-masked]">&lt;[email-masked]&gt;</a> wrote:

    Hi All,

    When running ibischk3 to check ver2.1 model, if there are warning
    messages complaining about "non-monotonic"and "extreme
currents present"
    around hundred amp level, is it possible and acceptible?

    Thanks

    ~eric

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 class="moz-txt-link-abbreviated" href="mailto:[email-masked]">[email-masked]</a>
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&lt;DIV&gt;&lt;SPAN class=3D434591623-16112002&gt;&lt;FONT face=3DArial
color=3D#0000ff =
size=3D2&gt;I'll=20
disagree on this.&amp;nbsp; The extreme currents are likely OK but the =
non-monotonic=20
warnings may cause the simulations to not converge properly
or in some=20
simulators cause the model not to load at all.&amp;nbsp; If the
sum of the =
IV curves=20
do not have monotonic issues you are OK.&amp;nbsp; If the sum of
the curves =
do have=20
monotonic issues I would investigate before I would say it is
OK.&amp;nbsp;=20
&lt;/FONT&gt;&lt;/SPAN&gt;&lt;/DIV&gt;
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&lt;DIV class=3DSection1&gt;
&lt;P style=3D"MARGIN: 0in 0in 0pt"&gt;&lt;SPAN=20
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&lt;P style=3D"MARGIN: 0in 0in 0pt"&gt;&lt;SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial"&gt;Device Modeling =
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Consulting Group =

LLC&lt;/SPAN&gt;&lt;/P&gt;
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&lt;P style=3D"MARGIN: 0in 0in 0pt"&gt;&lt;SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial"&gt;(503)
430-1065&lt;/SPAN&gt;&lt;/P&gt;
&lt;P style=3D"MARGIN: 0in 0in 0pt"&gt;&lt;SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Arial"&gt;<a
 class="moz-txt-link-abbreviated" href="mailto:[email-masked]">[email-masked]</a>&lt;/SPAN&gt;&lt;/P&gt;
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&lt;BLOCKQUOTE&gt;
  &lt;DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft&gt;&lt;FONT =
face=3DTahoma=20
  size=3D2&gt;-----Original Message-----&lt;BR&gt;&lt;B&gt;From:&lt;/B&gt;=20
  <a
 class="moz-txt-link-abbreviated"
 href="mailto:[email-masked]">[email-masked]</a> =
[<a
 class="moz-txt-link-freetext"
 href="mailto:[email-masked]">mailto:[email-masked]</a>]&lt;B&gt;On=20
  Behalf Of &lt;/B&gt;Abdulrahman A. Rafiq&lt;BR&gt;&lt;B&gt;Sent:&lt;/B&gt; Friday,
November =
15, 2002=20
  11:32 PM&lt;BR&gt;&lt;B&gt;To:&lt;/B&gt; Eric Hsu; =
<a class="moz-txt-link-abbreviated"
 href="mailto:[email-masked]">[email-masked]</a>&lt;BR&gt;&lt;B&gt;Subject:&lt;/B&gt;=20
  Re: [IBIS-Users] Question about warning message&lt;BR&gt;&lt;BR&gt;&lt;/FONT&gt;&lt;/DIV&gt;
  &lt;P&gt;Eric,=20
  &lt;P&gt;The warning message of "non-monotonic" is perfectly
acceptable and =
can be=20
  ignored. As for the warning message of extrreme currents
present, it =
also is=20
  acceptable. In fact if you open the .ibs file and comment
our all the =
extreme=20
  +ve and -ve currents in the I-V tables and then rerun
ibischks, this =
warning=20
  message will not show up.=20
  &lt;P&gt;In short you needn't worry too much about these warnings.=20
  &lt;P&gt;Hope this helps.=20
  &lt;P&gt;Regards,=20
  &lt;P&gt;Abdulrahman Rafiq=20
  &lt;P&gt;&amp;nbsp;&lt;B&gt;&lt;I&gt;Eric Hsu
&amp;lt;[email-masked]&amp;gt;&lt;/I&gt;&lt;/B&gt; wrote:=20
  &lt;BLOCKQUOTE=20
  style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT:
#1010ff 2px =
solid"&gt;Hi=20
    All,&lt;BR&gt;&lt;BR&gt;When running ibischk3 to check ver2.1 model,
if there =
are=20
    warning&lt;BR&gt;messages complaining about "non-monotonic"and
"extreme =
currents=20
    present"&lt;BR&gt;around hundred amp level, is it possible and=20
    =
acceptible?&lt;BR&gt;&lt;BR&gt;Thanks&lt;BR&gt;&lt;BR&gt;~eric&lt;BR&gt;&lt;BR&gt;|---------------
- -----------=
- ----------------------------------------&lt;BR&gt;|For=20
    help or to subscribe/unsubscribe, email
<a class="moz-txt-link-abbreviated" href="mailto:[email-masked]">[email-masked]</a>&lt;BR&gt;|with =
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    ibis &lt;OPTIONAL e-mail address, if different&gt;&lt;BR&gt;| subscribe =
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    address, if different&gt;&lt;BR&gt;|&lt;BR&gt;|or email a written request to=20
    <a
 class="moz-txt-link-abbreviated" href="mailto:[email-masked]">[email-masked]</a>.&lt;BR&gt;|&lt;BR&gt;|IBIS reflector archives exist=20
    under:&lt;BR&gt;|&lt;BR&gt;| <a
 class="moz-txt-link-freetext"
 href="http://www.eda.org/pub/ibis/email_archive/">http://www.eda.org/pub/ibis/email_archive/</a> =
Recent&lt;BR&gt;|=20
    <a
 class="moz-txt-link-freetext" href="http://www">http://www</a>.! eda.org/pub/ibis/users_archive/ Recent&lt;BR&gt;|=20
    <a
 class="moz-txt-link-freetext" href="http://www.eda.org/pub/ibis/email/">http://www.eda.org/pub/ibis/email/</a> E-mail since=20
  =
1993&lt;/BLOCKQUOTE&gt;&lt;BR&gt;&lt;BR&gt;************************************&lt;
BR&gt;ABDULRAH=
MAN=20
  AK RAFIQ&lt;BR&gt;Scientific Engineering Consultants,
Inc&lt;BR&gt;Phone: (805)=20
  708-1976&lt;BR&gt;Email: <a
 class="moz-txt-link-abbreviated" href="mailto:[email-masked]">[email-masked]</a> &lt;BR&gt;URL: =
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 href="http://www.geocities.com/arafiqsi/=20">www.geocities.com/arafiqsi/=20</a>
  &lt;BR&gt;************************************
  &lt;P&gt;&lt;BR&gt;
  &lt;HR SIZE=3D1&gt;
  Do you Yahoo!?&lt;BR&gt;&lt;A=20
  =
href=3D<a
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 href="http://rd.yahoo.com/hosting/mailsig/*http://webhosting.yahoo.com">"http://rd.yahoo.com/hosting/mailsig/*http://webhosting
.yahoo.com"</a>=
      </pre>
       
      <blockquote type="cite">         
        <pre wrap="">Yahoo!=20
        </pre>
       </blockquote>
       
      <pre wrap="">  Web Hosting&lt;/A&gt; - Let the expert host your =
site&lt;/BLOCKQUOTE&gt;&lt;/BODY&gt;&lt;/HTML&gt;

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      </pre>
     </blockquote>
     
    <pre wrap="">|------------------------------------------------------------------
|For help or to subscribe/unsubscribe, email <a
 class="moz-txt-link-abbreviated" href="mailto:[email-masked]">[email-masked]</a>
|with just the appropriate command message(s) in the body:
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    </pre>
   </blockquote>
   
  <pre wrap=""><!---->
  </pre>
 </blockquote>
 <br>
 
<pre class="moz-signature" cols="$mailwrapcol"></pre>
 <br>
 <br>
<pre class="moz-signature" cols="$mailwrapcol">-- 
Scott McMorrow
Teraspeed Consulting Group LLC
2926 SE Yamhill St.
Portland, OR 97214
(503) 239-5536
<a class="moz-txt-link-freetext" href="http://www.teraspeed.com">http://www.teraspeed.com</a>

</pre>
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------------------------------

Date: Tue, 19 Nov 2002 12:20:38 -0500
From: "Lynne Green" <[email-masked]>
Subject: RE: [IBIS-Users] Question about warning message]

Hi, Scott,

Having table values that cover -Vcc to 2Vcc is useful for DC convergence
for beginning a
transient (time-domain) simulation.  Fortunately, SI simulators are
smart enough to know
the DC operating point must lie between the reflection limits.
("General purpose" simulators
often do not assume a voltage range, so they can literally search "far
and wide".  This
makes them more sensitive to numeric overflow in model extrapolation.)

The easiest thing to do is to "clamp" the I-V table values outside the
range of "reasonable"
operation.  +/-100 Amps is a good limit, or any other value beyond the
expected currents
during maximum overshoots.

As noted by previous posters, the correct thing is to add resistance to
the SPICE diodes
for both output driver transistors and clamp diodes.

Best regards,
Lynne

- -----Original Message-----
From: Scott McMorrow [mailto:[email-masked]] 
Sent: Monday, November 18, 2002 10:31 PM
To: [email-masked]
Subject: Re: [IBIS-Users] Question about warning message]

Fred,

Damn!  You actually read the spec and are absolutely correct.  This is
something that really needs to be corrected, as it it quite
inappropriate for modern devices.

regards,

scott

\ 
- -- 
Scott McMorrow
Teraspeed Consulting Group LLC
2926 SE Yamhill St.
Portland, OR 97214
(503) 239-5536
http://www.teraspeed.com

Fred Balistreri wrote:

The reason IBIS models go from -Vcc to 2Vcc is because that is what it
says in the spec. The following is a direct quote from the spec,
immediately
following the section that describes the testing voltage range:

"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."

If we don't want people to follow the spec then I would argue that the
spec needs modification. More importantly because of the spec ibis tools
all
conform to the voltage testing as prescribed, included s2ibis which a
lot
of people use. So I don't think the statement about people blindly
following
the voltage requirement is true. It may be more of the case that
historically
this is what we have done, which can be traced back to where it all
started,
the specification itself.

Best Regards,

"Flora, Matthew" wrote:
  
Hi All,

The non-monotonic warnings are generated by the IBIS Golden Parser
because it is
not summing the I-V table together before checking for monotonicity.  I
believe
there is a pending bug (71) fix to the IBIS Golden Parser which will sum
the
tables before the monotonicity check.
http://www.vhdl.org/pub/ibis/bugs/ibischk/bug71

It has been argued that the extreme currents are acceptable because a
part
pushed to those extremes may actually give extreme current in the
instant before
it melts.  I believe this is because people are blindly following the
- -VCC to
2VCC voltage range recommendation for I-V tables and so are trying to
come up
with currents well outside of the normal operating region for some
parts.  I
don't know if the IBIS spec actually say it, but I believe the intention
is that
the I-V tables should include all of the voltages where "interesting"
things
happen.  If the part was never designed to handle voltages out at -VCC
or 2VCC,
then the tables need not include such voltages.  I believe this was more
common
when more people were doing bench measurements to make the tables and
they
limited the voltage range to actual voltages that got close to melt
down, but
not beyond.

Just my two pence,
Matthew Flora

- -----Original Message-----
From: Angulo, John
Sent: Monday, November 18, 2002 10:28 AM
To: [email-masked]'
Subject: RE: [IBIS-Users] Question about warning message

The following is posted on behalf of Tom Dagostino at
Teraspeed Consulting Group.  Please send any private replies
to [email-masked] only.

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

I'll disagree on this.  The extreme currents are likely OK but the
non-monotonic warnings may cause the simulations to not
converge properly or
in some simulators cause the model not to load at all.  If
the sum of the IV
curves do not have monotonic issues you are OK.  If the sum
of the curves do
have monotonic issues I would investigate before I would say it is OK.

Tom Dagostino

Device Modeling Division

Teraspeed Consulting Group LLC

2926 SE Yamhill St.

Portland, OR 97214

(503) 430-1065

[email-masked]

http://www.teraspeed.com

  -----Original Message-----
  From: [email-masked]
[mailto:[email-masked]]On Behalf Of
Abdulrahman A. Rafiq
  Sent: Friday, November 15, 2002 11:32 PM
  To: Eric Hsu; [email-masked]
  Subject: Re: [IBIS-Users] Question about warning message

  Eric,

  The warning message of "non-monotonic" is perfectly
acceptable and can be
ignored. As for the warning message of extrreme currents
present, it also is
acceptable. In fact if you open the .ibs file and comment our all the
extreme +ve and -ve currents in the I-V tables and then rerun
ibischks, this
warning message will not show up.

  In short you needn't worry too much about these warnings.

  Hope this helps.

  Regards,

  Abdulrahman Rafiq

   Eric Hsu <[email-masked]> wrote:

    Hi All,

    When running ibischk3 to check ver2.1 model, if there are warning
    messages complaining about "non-monotonic"and "extreme
currents present"
    around hundred amp level, is it possible and acceptible?

    Thanks

    ~eric

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

  ************************************
  ABDULRAHMAN AK RAFIQ
  Scientific Engineering Consultants, Inc
  Phone: (805) 708-1976
  Email: [email-masked]
  URL: www.geocities.com/arafiqsi/
  ************************************

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<DIV><SPAN class=3D434591623-16112002><FONT face=3DArial
color=3D#0000ff =
size=3D2>I'll=20
disagree on this.&nbsp; The extreme currents are likely OK but the =
non-monotonic=20
warnings may cause the simulations to not converge properly
or in some=20
simulators cause the model not to load at all.&nbsp; If the
sum of the =
IV curves=20
do not have monotonic issues you are OK.&nbsp; If the sum of
the curves =
do have=20
monotonic issues I would investigate before I would say it is
OK.&nbsp;=20
</FONT></SPAN></DIV>
<DIV>&nbsp;</DIV>
<DIV class=3DSection1>
<P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Tom Dagostino</SPAN></P>
<P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Device Modeling =
Division</SPAN></P>
<P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Teraspeed
Consulting Group =

LLC</SPAN></P>
<P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">2926 SE Yamhill =
St.</SPAN></P>
<P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Portland, OR =
97214</SPAN></P>
<P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">(503)
430-1065</SPAN></P>
<P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Arial">[email-masked]</SPAN></P>
<P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Arial">http://www.teraspeed.com</SPAN></P></DIV>
<BLOCKQUOTE>
  <DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
  size=3D2>-----Original Message-----<BR><B>From:</B>=20
  [email-masked] =
[mailto:[email-masked]]<B>On=20
  Behalf Of </B>Abdulrahman A. Rafiq<BR><B>Sent:</B> Friday,
November =
15, 2002=20
  11:32 PM<BR><B>To:</B> Eric Hsu; =
[email-masked]<BR><B>Subject:</B>=20
  Re: [IBIS-Users] Question about warning message<BR><BR></FONT></DIV>
  <P>Eric,=20
  <P>The warning message of "non-monotonic" is perfectly
acceptable and =
can be=20
  ignored. As for the warning message of extrreme currents
present, it =
also is=20
  acceptable. In fact if you open the .ibs file and comment
our all the =
extreme=20
  +ve and -ve currents in the I-V tables and then rerun
ibischks, this =
warning=20
  message will not show up.=20
  <P>In short you needn't worry too much about these warnings.=20
  <P>Hope this helps.=20
  <P>Regards,=20
  <P>Abdulrahman Rafiq=20
  <P>&nbsp;<B><I>Eric Hsu
&lt;[email-masked]&gt;</I></B> wrote:=20
  <BLOCKQUOTE=20
  style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT:
#1010ff 2px =
solid">Hi=20
    All,<BR><BR>When running ibischk3 to check ver2.1 model,
if there =
are=20
    warning<BR>messages complaining about "non-monotonic"and
"extreme =
currents=20
    present"<BR>around hundred amp level, is it possible and=20
    =
acceptible?<BR><BR>Thanks<BR><BR>~eric<BR><BR>|---------------
- -----------=
- ----------------------------------------<BR>|For=20
    help or to subscribe/unsubscribe, email
[email-masked]<BR>|with =
just the=20
    appropriate command message(s) in the body:<BR>|<BR>| help<BR>| =
subscribe=20
    ibis <OPTIONAL e-mail address, if different><BR>| subscribe =
ibis-users=20
    <OPTIONAL e-mail address, if different><BR>| unsubscribe ibis =
<OPTIONAL=20
    e-mail address, if different><BR>| unsubscribe ibis-users
<OPTIONAL =
e-mail=20
    address, if different><BR>|<BR>|or email a written request to=20
    [email-masked].<BR>|<BR>|IBIS reflector archives exist=20
    under:<BR>|<BR>| http://www.eda.org/pub/ibis/email_archive/ =
Recent<BR>|=20
    http://www.! eda.org/pub/ibis/users_archive/ Recent<BR>|=20
    http://www.eda.org/pub/ibis/email/ E-mail since=20
  =
1993</BLOCKQUOTE><BR><BR>************************************<
BR>ABDULRAH=
MAN=20
  AK RAFIQ<BR>Scientific Engineering Consultants,
Inc<BR>Phone: (805)=20
  708-1976<BR>Email: [email-masked] <BR>URL: =
www.geocities.com/arafiqsi/=20
  <BR>************************************
  <P><BR>
  <HR SIZE=3D1>
  Do you Yahoo!?<BR><A=20
  =
href=3D"http://rd.yahoo.com/hosting/mailsig/*http://webhosting
.yahoo.com"=
      
Yahoo!=20
        
  Web Hosting</A> - Let the expert host your =
site</BLOCKQUOTE></BODY></HTML>

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- -- 
Scott McMorrow
Teraspeed Consulting Group LLC
2926 SE Yamhill St.
Portland, OR 97214
(503) 239-5536
http://www.teraspeed.com
|------------------------------------------------------------------
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------------------------------

Date: Tue, 19 Nov 2002 10:14:46 -0800
From: Fred Balistreri <[email-masked]>
Subject: Re: [IBIS-Users] Question about warning message]

I believe the original reason for testing from -vcc to 2vcc
had to do with transmission line theory. The possible maximum
reflection with an open circuit becomes the 2*voltage of the
driving line given that the reflection coeficient becomes
infinite. Oddly enough once there are diodes and esd circuitry
reaching such voltages becomes difficult. In point of fact
this is what we wish to determine. So while setting these limits
is general and perhaps should be the default it is sometimes
not necessary. In fact often times it is not possible or only
possible through the magic of simulation. As pointed out the
wording in the IBIS spec makes it mandatory. However a part
will pass the parser even if the mandatory voltages are not
achieved. I also am not voluntering to write a bird but perhaps
one is in order.

I do not think the model maker should be fideling with the SPICE
netlist unless they are the ones who know the design. At the
same time I agree with Kim that better attention needs to be 
paid to the SPICE models. The IC vendors need to realize what
the application of the model is for. Instead what seems to
happen is that the SPICE model gets thrown over the wall to
a field organization that simply passes it on to the outside
world as is or creates an IBIS model from it.

Best Regards,

Lynne Green wrote:
> 
> Hi, Scott,
> 
> Having table values that cover -Vcc to 2Vcc is useful for DC convergence
> for beginning a
> transient (time-domain) simulation.  Fortunately, SI simulators are
> smart enough to know
> the DC operating point must lie between the reflection limits.
> ("General purpose" simulators
> often do not assume a voltage range, so they can literally search "far
> and wide".  This
> makes them more sensitive to numeric overflow in model extrapolation.)
> 
> The easiest thing to do is to "clamp" the I-V table values outside the
> range of "reasonable"
> operation.  +/-100 Amps is a good limit, or any other value beyond the
> expected currents
> during maximum overshoots.
> 
> As noted by previous posters, the correct thing is to add resistance to
> the SPICE diodes
> for both output driver transistors and clamp diodes.
> 
> Best regards,
> Lynne
> 
> -----Original Message-----
> From: Scott McMorrow [mailto:[email-masked]]
> Sent: Monday, November 18, 2002 10:31 PM
> To: [email-masked]
> Subject: Re: [IBIS-Users] Question about warning message]
> 
> Fred,
> 
> Damn!  You actually read the spec and are absolutely correct.  This is
> something that really needs to be corrected, as it it quite
> inappropriate for modern devices.
> 
> regards,
> 
> scott
> 
> \
> --
> Scott McMorrow
> Teraspeed Consulting Group LLC
> 2926 SE Yamhill St.
> Portland, OR 97214
> (503) 239-5536
> http://www.teraspeed.com
> 
> Fred Balistreri wrote:
> 
> The reason IBIS models go from -Vcc to 2Vcc is because that is what it
> says in the spec. The following is a direct quote from the spec,
> immediately
> following the section that describes the testing voltage range:
> 
> "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."
> 
> If we don't want people to follow the spec then I would argue that the
> spec needs modification. More importantly because of the spec ibis tools
> all
> conform to the voltage testing as prescribed, included s2ibis which a
> lot
> of people use. So I don't think the statement about people blindly
> following
> the voltage requirement is true. It may be more of the case that
> historically
> this is what we have done, which can be traced back to where it all
> started,
> the specification itself.
> 
> Best Regards,
> 
> "Flora, Matthew" wrote:
> 
> Hi All,
> 
> The non-monotonic warnings are generated by the IBIS Golden Parser
> because it is
> not summing the I-V table together before checking for monotonicity.  I
> believe
> there is a pending bug (71) fix to the IBIS Golden Parser which will sum
> the
> tables before the monotonicity check.
> http://www.vhdl.org/pub/ibis/bugs/ibischk/bug71
> 
> It has been argued that the extreme currents are acceptable because a
> part
> pushed to those extremes may actually give extreme current in the
> instant before
> it melts.  I believe this is because people are blindly following the
> -VCC to
> 2VCC voltage range recommendation for I-V tables and so are trying to
> come up
> with currents well outside of the normal operating region for some
> parts.  I
> don't know if the IBIS spec actually say it, but I believe the intention
> is that
> the I-V tables should include all of the voltages where "interesting"
> things
> happen.  If the part was never designed to handle voltages out at -VCC
> or 2VCC,
> then the tables need not include such voltages.  I believe this was more
> common
> when more people were doing bench measurements to make the tables and
> they
> limited the voltage range to actual voltages that got close to melt
> down, but
> not beyond.
> 
> Just my two pence,
> Matthew Flora
> 
> 
> -----Original Message-----
> From: Angulo, John
> Sent: Monday, November 18, 2002 10:28 AM
> To: [email-masked]'
> Subject: RE: [IBIS-Users] Question about warning message
> 
> The following is posted on behalf of Tom Dagostino at
> Teraspeed Consulting Group.  Please send any private replies
> to [email-masked] only.
> 
> ----------------------------------------------------------------
> 
> I'll disagree on this.  The extreme currents are likely OK but the
> non-monotonic warnings may cause the simulations to not
> converge properly or
> in some simulators cause the model not to load at all.  If
> the sum of the IV
> curves do not have monotonic issues you are OK.  If the sum
> of the curves do
> have monotonic issues I would investigate before I would say it is OK.
> 
> Tom Dagostino
> 
> Device Modeling Division
> 
> Teraspeed Consulting Group LLC
> 
> 2926 SE Yamhill St.
> 
> Portland, OR 97214
> 
> (503) 430-1065
> 
> [email-masked]
> 
> http://www.teraspeed.com
> 
>   -----Original Message-----
>   From: [email-masked]
> [mailto:[email-masked]]On Behalf Of
> Abdulrahman A. Rafiq
>   Sent: Friday, November 15, 2002 11:32 PM
>   To: Eric Hsu; [email-masked]
>   Subject: Re: [IBIS-Users] Question about warning message
> 
>   Eric,
> 
>   The warning message of "non-monotonic" is perfectly
> acceptable and can be
> ignored. As for the warning message of extrreme currents
> present, it also is
> acceptable. In fact if you open the .ibs file and comment our all the
> extreme +ve and -ve currents in the I-V tables and then rerun
> ibischks, this
> warning message will not show up.
> 
>   In short you needn't worry too much about these warnings.
> 
>   Hope this helps.
> 
>   Regards,
> 
>   Abdulrahman Rafiq
> 
>    Eric Hsu <[email-masked]> wrote:
> 
>     Hi All,
> 
>     When running ibischk3 to check ver2.1 model, if there are warning
>     messages complaining about "non-monotonic"and "extreme
> currents present"
>     around hundred amp level, is it possible and acceptible?
> 
>     Thanks
> 
>     ~eric
> 
> |------------------------------------------------------------------
>     |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
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>     | http://www.eda.org/pub/ibis/email/ E-mail since 1993
> 
>   ************************************
>   ABDULRAHMAN AK RAFIQ
>   Scientific Engineering Consultants, Inc
>   Phone: (805) 708-1976
>   Email: [email-masked]
>   URL: www.geocities.com/arafiqsi/
>   ************************************
> 
> --------------------------------------------------------------
> --------------
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> <BODY>
> <DIV><SPAN class=3D434591623-16112002><FONT face=3DArial
> color=3D#0000ff =
> size=3D2>I'll=20
> disagree on this.&nbsp; The extreme currents are likely OK but the =
> non-monotonic=20
> warnings may cause the simulations to not converge properly
> or in some=20
> simulators cause the model not to load at all.&nbsp; If the
> sum of the =
> IV curves=20
> do not have monotonic issues you are OK.&nbsp; If the sum of
> the curves =
> do have=20
> monotonic issues I would investigate before I would say it is
> OK.&nbsp;=20
> </FONT></SPAN></DIV>
> <DIV>&nbsp;</DIV>
> <DIV class=3DSection1>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Tom Dagostino</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Device Modeling =
> Division</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Teraspeed
> Consulting Group =
> 
> LLC</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">2926 SE Yamhill =
> St.</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Portland, OR =
> 97214</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">(503)
> 430-1065</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
> Arial">[email-masked]</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
> Arial">http://www.teraspeed.com</SPAN></P></DIV>
> <BLOCKQUOTE>
>   <DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
> face=3DTahoma=20
>   size=3D2>-----Original Message-----<BR><B>From:</B>=20
>   [email-masked] =
> [mailto:[email-masked]]<B>On=20
>   Behalf Of </B>Abdulrahman A. Rafiq<BR><B>Sent:</B> Friday,
> November =
> 15, 2002=20
>   11:32 PM<BR><B>To:</B> Eric Hsu; =
> [email-masked]<BR><B>Subject:</B>=20
>   Re: [IBIS-Users] Question about warning message<BR><BR></FONT></DIV>
>   <P>Eric,=20
>   <P>The warning message of "non-monotonic" is perfectly
> acceptable and =
> can be=20
>   ignored. As for the warning message of extrreme currents
> present, it =
> also is=20
>   acceptable. In fact if you open the .ibs file and comment
> our all the =
> extreme=20
>   +ve and -ve currents in the I-V tables and then rerun
> ibischks, this =
> warning=20
>   message will not show up.=20
>   <P>In short you needn't worry too much about these warnings.=20
>   <P>Hope this helps.=20
>   <P>Regards,=20
>   <P>Abdulrahman Rafiq=20
>   <P>&nbsp;<B><I>Eric Hsu
> &lt;[email-masked]&gt;</I></B> wrote:=20
>   <BLOCKQUOTE=20
>   style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT:
> #1010ff 2px =
> solid">Hi=20
>     All,<BR><BR>When running ibischk3 to check ver2.1 model,
> if there =
> are=20
>     warning<BR>messages complaining about "non-monotonic"and
> "extreme =
> currents=20
>     present"<BR>around hundred amp level, is it possible and=20
>     =
> acceptible?<BR><BR>Thanks<BR><BR>~eric<BR><BR>|---------------
> -----------=
> ----------------------------------------<BR>|For=20
>     help or to subscribe/unsubscribe, email
> [email-masked]<BR>|with =
> just the=20
>     appropriate command message(s) in the body:<BR>|<BR>| help<BR>| =
> subscribe=20
>     ibis <OPTIONAL e-mail address, if different><BR>| subscribe =
> ibis-users=20
>     <OPTIONAL e-mail address, if different><BR>| unsubscribe ibis =
> <OPTIONAL=20
>     e-mail address, if different><BR>| unsubscribe ibis-users
> <OPTIONAL =
> e-mail=20
>     address, if different><BR>|<BR>|or email a written request to=20
>     [email-masked].<BR>|<BR>|IBIS reflector archives exist=20
>     under:<BR>|<BR>| http://www.eda.org/pub/ibis/email_archive/ =
> Recent<BR>|=20
>     http://www.! eda.org/pub/ibis/users_archive/ Recent<BR>|=20
>     http://www.eda.org/pub/ibis/email/ E-mail since=20
>   =
> 1993</BLOCKQUOTE><BR><BR>************************************<
> BR>ABDULRAH=
> MAN=20
>   AK RAFIQ<BR>Scientific Engineering Consultants,
> Inc<BR>Phone: (805)=20
>   708-1976<BR>Email: [email-masked] <BR>URL: =
> www.geocities.com/arafiqsi/=20
>   <BR>************************************
>   <P><BR>
>   <HR SIZE=3D1>
>   Do you Yahoo!?<BR><A=20
>   =
> href=3D"http://rd.yahoo.com/hosting/mailsig/*http://webhosting
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> 
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> 
>   Web Hosting</A> - Let the expert host your =
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> |
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> 
> 
> 
> 
> --
> Scott McMorrow
> Teraspeed Consulting Group LLC
> 2926 SE Yamhill St.
> Portland, OR 97214
> (503) 239-5536
> http://www.teraspeed.com
> |------------------------------------------------------------------
> |For help or to subscribe/unsubscribe, email [email-masked]
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------------------------------

Date: Tue, 19 Nov 2002 10:48:21 -0800
From: "Tom Dagostino" <[email-masked]>
Subject: RE: [IBIS-Users] Question about warning message]

I totally agree about the quality of SPICE models.  I've seen too many SPICE
based IBIS models that do not predict the actual behavior of the silicon.
And I'm not just talking about clamps.  Too often the pullup or pulldown
measurements made on a die will fall outside the range predicted by SPICE.

So, is -Vcc to 2Vcc enough?  Consider the 3.3V, 5 Volt compliant receiver on
the end of an unterminated net with a 5 volt CMOS driver.   Seems the part
could see almost +10 Volts.

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

- -----Original Message-----
From: [email-masked]
[mailto:[email-masked]]On Behalf Of Fred Balistreri
Sent: Tuesday, November 19, 2002 10:15 AM
To: Lynne Green
Cc: [email-masked]; [email-masked]
Subject: Re: [IBIS-Users] Question about warning message]

I believe the original reason for testing from -vcc to 2vcc
had to do with transmission line theory. The possible maximum
reflection with an open circuit becomes the 2*voltage of the
driving line given that the reflection coeficient becomes
infinite. Oddly enough once there are diodes and esd circuitry
reaching such voltages becomes difficult. In point of fact
this is what we wish to determine. So while setting these limits
is general and perhaps should be the default it is sometimes
not necessary. In fact often times it is not possible or only
possible through the magic of simulation. As pointed out the
wording in the IBIS spec makes it mandatory. However a part
will pass the parser even if the mandatory voltages are not
achieved. I also am not voluntering to write a bird but perhaps
one is in order.

I do not think the model maker should be fideling with the SPICE
netlist unless they are the ones who know the design. At the
same time I agree with Kim that better attention needs to be
paid to the SPICE models. The IC vendors need to realize what
the application of the model is for. Instead what seems to
happen is that the SPICE model gets thrown over the wall to
a field organization that simply passes it on to the outside
world as is or creates an IBIS model from it.

Best Regards,

Lynne Green wrote:
>
> Hi, Scott,
>
> Having table values that cover -Vcc to 2Vcc is useful for DC convergence
> for beginning a
> transient (time-domain) simulation.  Fortunately, SI simulators are
> smart enough to know
> the DC operating point must lie between the reflection limits.
> ("General purpose" simulators
> often do not assume a voltage range, so they can literally search "far
> and wide".  This
> makes them more sensitive to numeric overflow in model extrapolation.)
>
> The easiest thing to do is to "clamp" the I-V table values outside the
> range of "reasonable"
> operation.  +/-100 Amps is a good limit, or any other value beyond the
> expected currents
> during maximum overshoots.
>
> As noted by previous posters, the correct thing is to add resistance to
> the SPICE diodes
> for both output driver transistors and clamp diodes.
>
> Best regards,
> Lynne
>
> -----Original Message-----
> From: Scott McMorrow [mailto:[email-masked]]
> Sent: Monday, November 18, 2002 10:31 PM
> To: [email-masked]
> Subject: Re: [IBIS-Users] Question about warning message]
>
> Fred,
>
> Damn!  You actually read the spec and are absolutely correct.  This is
> something that really needs to be corrected, as it it quite
> inappropriate for modern devices.
>
> regards,
>
> scott
>
> \
> --
> Scott McMorrow
> Teraspeed Consulting Group LLC
> 2926 SE Yamhill St.
> Portland, OR 97214
> (503) 239-5536
> http://www.teraspeed.com
>
> Fred Balistreri wrote:
>
> The reason IBIS models go from -Vcc to 2Vcc is because that is what it
> says in the spec. The following is a direct quote from the spec,
> immediately
> following the section that describes the testing voltage range:
>
> "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."
>
> If we don't want people to follow the spec then I would argue that the
> spec needs modification. More importantly because of the spec ibis tools
> all
> conform to the voltage testing as prescribed, included s2ibis which a
> lot
> of people use. So I don't think the statement about people blindly
> following
> the voltage requirement is true. It may be more of the case that
> historically
> this is what we have done, which can be traced back to where it all
> started,
> the specification itself.
>
> Best Regards,
>
> "Flora, Matthew" wrote:
>
> Hi All,
>
> The non-monotonic warnings are generated by the IBIS Golden Parser
> because it is
> not summing the I-V table together before checking for monotonicity.  I
> believe
> there is a pending bug (71) fix to the IBIS Golden Parser which will sum
> the
> tables before the monotonicity check.
> http://www.vhdl.org/pub/ibis/bugs/ibischk/bug71
>
> It has been argued that the extreme currents are acceptable because a
> part
> pushed to those extremes may actually give extreme current in the
> instant before
> it melts.  I believe this is because people are blindly following the
> -VCC to
> 2VCC voltage range recommendation for I-V tables and so are trying to
> come up
> with currents well outside of the normal operating region for some
> parts.  I
> don't know if the IBIS spec actually say it, but I believe the intention
> is that
> the I-V tables should include all of the voltages where "interesting"
> things
> happen.  If the part was never designed to handle voltages out at -VCC
> or 2VCC,
> then the tables need not include such voltages.  I believe this was more
> common
> when more people were doing bench measurements to make the tables and
> they
> limited the voltage range to actual voltages that got close to melt
> down, but
> not beyond.
>
> Just my two pence,
> Matthew Flora
>
>
> -----Original Message-----
> From: Angulo, John
> Sent: Monday, November 18, 2002 10:28 AM
> To: [email-masked]'
> Subject: RE: [IBIS-Users] Question about warning message
>
> The following is posted on behalf of Tom Dagostino at
> Teraspeed Consulting Group.  Please send any private replies
> to [email-masked] only.
>
> ----------------------------------------------------------------
>
> I'll disagree on this.  The extreme currents are likely OK but the
> non-monotonic warnings may cause the simulations to not
> converge properly or
> in some simulators cause the model not to load at all.  If
> the sum of the IV
> curves do not have monotonic issues you are OK.  If the sum
> of the curves do
> have monotonic issues I would investigate before I would say it is OK.
>
> Tom Dagostino
>
> Device Modeling Division
>
> Teraspeed Consulting Group LLC
>
> 2926 SE Yamhill St.
>
> Portland, OR 97214
>
> (503) 430-1065
>
> [email-masked]
>
> http://www.teraspeed.com
>
>   -----Original Message-----
>   From: [email-masked]
> [mailto:[email-masked]]On Behalf Of
> Abdulrahman A. Rafiq
>   Sent: Friday, November 15, 2002 11:32 PM
>   To: Eric Hsu; [email-masked]
>   Subject: Re: [IBIS-Users] Question about warning message
>
>   Eric,
>
>   The warning message of "non-monotonic" is perfectly
> acceptable and can be
> ignored. As for the warning message of extrreme currents
> present, it also is
> acceptable. In fact if you open the .ibs file and comment our all the
> extreme +ve and -ve currents in the I-V tables and then rerun
> ibischks, this
> warning message will not show up.
>
>   In short you needn't worry too much about these warnings.
>
>   Hope this helps.
>
>   Regards,
>
>   Abdulrahman Rafiq
>
>    Eric Hsu <[email-masked]> wrote:
>
>     Hi All,
>
>     When running ibischk3 to check ver2.1 model, if there are warning
>     messages complaining about "non-monotonic"and "extreme
> currents present"
>     around hundred amp level, is it possible and acceptible?
>
>     Thanks
>
>     ~eric
>
> |------------------------------------------------------------------
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> <BODY>
> <DIV><SPAN class=3D434591623-16112002><FONT face=3DArial
> color=3D#0000ff =
> size=3D2>I'll=20
> disagree on this.&nbsp; The extreme currents are likely OK but the =
> non-monotonic=20
> warnings may cause the simulations to not converge properly
> or in some=20
> simulators cause the model not to load at all.&nbsp; If the
> sum of the =
> IV curves=20
> do not have monotonic issues you are OK.&nbsp; If the sum of
> the curves =
> do have=20
> monotonic issues I would investigate before I would say it is
> OK.&nbsp;=20
> </FONT></SPAN></DIV>
> <DIV>&nbsp;</DIV>
> <DIV class=3DSection1>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Tom Dagostino</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Device Modeling =
> Division</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Teraspeed
> Consulting Group =
>
> LLC</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">2926 SE Yamhill =
> St.</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">Portland, OR =
> 97214</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">(503)
> 430-1065</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
> Arial">[email-masked]</SPAN></P>
> <P style=3D"MARGIN: 0in 0in 0pt"><SPAN=20
> style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
> Arial">http://www.teraspeed.com</SPAN></P></DIV>
> <BLOCKQUOTE>
>   <DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
> face=3DTahoma=20
>   size=3D2>-----Original Message-----<BR><B>From:</B>=20
>   [email-masked] =
> [mailto:[email-masked]]<B>On=20
>   Behalf Of </B>Abdulrahman A. Rafiq<BR><B>Sent:</B> Friday,
> November =
> 15, 2002=20
>   11:32 PM<BR><B>To:</B> Eric Hsu; =
> [email-masked]<BR><B>Subject:</B>=20
>   Re: [IBIS-Users] Question about warning message<BR><BR></FONT></DIV>
>   <P>Eric,=20
>   <P>The warning message of "non-monotonic" is perfectly
> acceptable and =
> can be=20
>   ignored. As for the warning message of extrreme currents
> present, it =
> also is=20
>   acceptable. In fact if you open the .ibs file and comment
> our all the =
> extreme=20
>   +ve and -ve currents in the I-V tables and then rerun
> ibischks, this =
> warning=20
>   message will not show up.=20
>   <P>In short you needn't worry too much about these warnings.=20
>   <P>Hope this helps.=20
>   <P>Regards,=20
>   <P>Abdulrahman Rafiq=20
>   <P>&nbsp;<B><I>Eric Hsu
> &lt;[email-masked]&gt;</I></B> wrote:=20
>   <BLOCKQUOTE=20
>   style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT:
> #1010ff 2px =
> solid">Hi=20
>     All,<BR><BR>When running ibischk3 to check ver2.1 model,
> if there =
> are=20
>     warning<BR>messages complaining about "non-monotonic"and
> "extreme =
> currents=20
>     present"<BR>around hundred amp level, is it possible and=20
>     =
> acceptible?<BR><BR>Thanks<BR><BR>~eric<BR><BR>|---------------
> -----------=
> ----------------------------------------<BR>|For=20
>     help or to subscribe/unsubscribe, email
> [email-masked]<BR>|with =
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>   708-1976<BR>Email: [email-masked] <BR>URL: =
> www.geocities.com/arafiqsi/=20
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> --
> Scott McMorrow
> Teraspeed Consulting Group LLC
> 2926 SE Yamhill St.
> Portland, OR 97214
> (503) 239-5536
> http://www.teraspeed.com
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- --
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[email-masked]

http://www.apsimtech.com
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------------------------------

Date: Tue, 19 Nov 2002 22:01:23 -0800
From: Shee Kian Wong <[email-masked]>
Subject: [IBIS-Users] IBIS?

- ------_=_NextPart_001_01C2905A.416771F0
Content-Type: text/plain;
	charset="iso-8859-1"

Hi all,

I have several IBIS questions:
 
1.	I was wondering how an IBIS simulator read and interpret the data
tabulated in an IBIS file? What is the common algorithm used by most of the
simulators? For example a simple driver and receiver 	interconnected by a
transmission line. And the simulation shows the following waveform captured
at both ends:

			 <<...OLE_Obj...>> 

	Then how do the data in pullup/pulldown/clamp/ramp play their roles
in forming the simulation waveform? Can one tell what data constitute to a
particular portion of the waveform?    

2.	Lumped RLC package is often used in IBIS models. Can they be used in
higher frequency environment? Will parasitics in an IBIS file
(c_comp,C_pkg,C_pin,L_pkg,L_pin) alter the output impedance as
	operating frequency goes higher? Is there a maximum frequency that a
package model can withstand?

	If that is the case, is distributed package model a better choice?
How do we go about it?

Can someone shed some light here?

Have a nice day.
Thks & Rgds,
 
Shee Kian Wong

- ------_=_NextPart_001_01C2905A.416771F0
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<META HTTP-EQUIV=3D"Content-Type" CONTENT=3D"text/html; =
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<TITLE>IBIS?</TITLE>
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<BODY>

<P><FONT SIZE=3D2 FACE=3D"Arial">Hi all,</FONT>
</P>

<P><FONT SIZE=3D2 FACE=3D"Arial">I have several IBIS questions:</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">&nbsp;</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">1.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; I =
was wondering how an IBIS simulator read and interpret the data =
tabulated in an IBIS file? What is the common algorithm used by most of =
the simulators? For example </FONT><FONT COLOR=3D"#000000" SIZE=3D2 =
FACE=3D"Arial">a simple driver and receiver &nbsp;&nbsp;&nbsp;&nbsp; =
interconnected by a transmission line. And the simulation shows the =
following waveform captured at both ends:</FONT></P>

<P>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<FONT FACE=3D"Arial" SIZE=3D2 =
COLOR=3D"#000000"> &lt;&lt;...OLE_Obj...&gt;&gt; </FONT>
</P>

<P>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <FONT COLOR=3D"#000000" =
SIZE=3D2 FACE=3D"Arial">Then how do the data in =
pullup/pulldown/clamp/ramp play their roles in forming the simulation =
waveform? Can one tell what data constitute to a particular portion of =
the waveform?&nbsp;&nbsp;&nbsp; </FONT></P>

<P><FONT COLOR=3D"#000000" SIZE=3D2 =
FACE=3D"Arial">2.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Lumped RLC package is =
often used in IBIS models. Can they be used in higher frequency =
environment? Will parasitics in an IBIS file =
(c_comp,C_pkg,C_pin,L_pkg,L_pin) alter the output impedance =
as</FONT></P>

<P>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <FONT COLOR=3D"#000000" =
SIZE=3D2 FACE=3D"Arial">operating frequency goes higher? Is there a =
maximum frequency that a package model can withstand?</FONT>
</P>

<P>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <FONT COLOR=3D"#000000" =
SIZE=3D2 FACE=3D"Arial">If that is the case, is distributed package =
model a better choice? How do we go about it?</FONT>
</P>

<P><FONT SIZE=3D2 FACE=3D"Arial">Can someone shed some light =
here?</FONT>
</P>

<P><FONT COLOR=3D"#0000FF" SIZE=3D2 FACE=3D"Arial">Have a nice =
day.</FONT>
<BR><FONT COLOR=3D"#0000FF" SIZE=3D2 FACE=3D"Arial">Thks &amp; =
Rgds,</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Arial">=A0</FONT>
<BR><B><I><FONT COLOR=3D"#0000FF" SIZE=3D2 FACE=3D"Arial">Shee Kian =
Wong</FONT></I></B><I></I>
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------------------------------

Date: Wed, 20 Nov 2002 17:01:02 +0530
From: Nirav Patel <[email-masked]>
Subject: [IBIS-Users] spice parasitic to ibis pkg parasitic creation

This is a multi-part message in MIME format.
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Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

IBIS Gurus,

How to convert spice format package parasitic (*.cir file) to 
IBIS pacakge format (*.pkg file)?
For reference, sample file is attached. Are there any scripts
available to convert them in any other friendly format?

Thanks,
- -Nirav
- --------------97BCC3F6BF5E9E1F9E5FB7B3
Content-Type: text/plain; charset=us-ascii;
 name="tmp.cir"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="tmp.cir"

**This file generated on: Tue Nov 19 14:10:29 2002
** Version = 7.033000 **

.subckt PKG52(
+ Pin1  Pin2  Pin3  Pin4  Pin5  Pin6  Pin7  Pin8  Pin9  Pin10 
+ Pin11  Pin12  Pin13  Pin14  Pin15  Pin16  Pin17  Pin18  Pin19  Pin20 
+ Pin21  Pin22  Pin23  Pin24  Pin25  Pin26  Pin27  Pin28  Pin29  Pin30 
+ Pin31  Pin32  Pin33  Pin34  Pin35  Pin36  Pin37  Pin38  Pin39  Pin40 
+ Pin41  Pin42  Pin43  Pin44  Pin45  Pin46  Pin47  Pin48  Pin49  Pin50 
+ Pin51  Pin52 
+ bp1  bp2  bp3  bp4  bp5  bp6  bp7  bp8  bp9  bp10 
+ bp11  bp12  bp13  bp14  bp15  bp16  bp17  bp18  bp19  bp20 
+ bp21  bp22  bp23  bp24  bp25  bp26  bp27  bp28  bp29  bp30 
+ bp31  bp32  bp33  bp34  bp35  bp36  bp37  bp38  bp39  bp40 
+ bp41  bp42  bp43  bp44  bp45  bp46  bp47  bp48  bp49  bp50 
+ bp51  bp52 
+ pad gnd)
** Capacitance from die paddle to ckt brd gnd plane **
cpad pad gnd   2.11p
** lead 1 **
rcnt1 pin1 p1l 10m
l1l p1l sk1l1 1.05n
r1l1 sk1l1 p1t 4.76m
l1t p1t sk1t1 0.75n
r1t1 sk1t1 p1w 4.23m
l1w p1w sk1w1 2.53n
r1w1 sk1w1 bp1 138.50m
c1l p1t gnd 0.14p
c1w p1w gnd 0.07p
c1p p1w pad 0.14p
k1l1 l1l l2l 0.41
k1t1 l1t l2t 0.44
k1w1 l1w l2w 0.36
c1l1 p1t p2t 0.08p
c1w1 p1w p2w 0.09p
k1l2 l1l l3l 0.24
k1t2 l1t l3t 0.24
k1w2 l1w l3w 0.24
k1l3 l1l l4l 0.17
k1l4 l1l l5l 0.14
k1l5 l1l l6l 0.11
k1l6 l1l l7l 0.10
k1l7 l1l l8l 0.09
k1l8 l1l l9l 0.08
k1l9 l1l l10l 0.07
k1l10 l1l l11l 0.06
k1w3 l1w l4w 0.18
k1w4 l1w l5w 0.14
k1w5 l1w l6w 0.11
.
. 
.
.finis

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

Date: Wed, 20 Nov 2002 08:27:26 -0600
From: "Fisher, Thomas" <[email-masked]>
Subject: [IBIS-Users] Modeling Transient Suppressor

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All,
	Has anyone every heard of generating an IBIS model for a transient
suppressor?  For those not familiar with these devices they are used to
shunt energy surges away from expensive ASIC's and primarily consist of
bipolar transistors that turn on fast and can handle the high currents.
(I've included a URL for reference)  The question is, when modeling such a
device would you treat the cathode end of these diodes like that of a TTL
input and sweep it over the intended voltage range?  
	Thoughts/ideas are welcome.  Thanks.  

http://focus.ti.com/docs/prod/productfolder.jhtml?genericPartNumber=SN75240

Regards,
Thomas Fisher
Senior Systems Engineer
Texas Instruments, Inc.		Business: 214 480-3736
P.O. Box 660199 MS8710		Fax:      214 480-3160
Dallas, TX 75266-0199		[mailto:[email-masked]]

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<META HTTP-EQUIV=3D"Content-Type" CONTENT=3D"text/html; =
charset=3Diso-8859-1">
<META NAME=3D"Generator" CONTENT=3D"MS Exchange Server version =
5.5.2655.35">
<TITLE>Modeling Transient Suppressor</TITLE>
</HEAD>
<BODY>

<P><FONT SIZE=3D2 FACE=3D"Arial">All,</FONT>
<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <FONT SIZE=3D2 =
FACE=3D"Arial">Has anyone every heard of generating an IBIS model for a =
transient suppressor?&nbsp; For those not familiar with these devices =
they are used to shunt energy surges away from expensive ASIC's and =
primarily consist of bipolar transistors that turn on fast and can =
handle the high currents.&nbsp; (I've included a URL for =
reference)&nbsp; The question is, when modeling such a device would you =
treat the cathode end of these diodes like that of a TTL input and =
sweep it over the intended voltage range?&nbsp; </FONT></P>

<P>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <FONT SIZE=3D2 =
FACE=3D"Arial">Thoughts/ideas are welcome.&nbsp; Thanks.&nbsp; </FONT>
</P>

<P><FONT SIZE=3D2 FACE=3D"Arial"><A =
HREF=3D"http://focus.ti.com/docs/prod/productfolder.jhtml?genericPartNum=
ber=3DSN75240" =
TARGET=3D"_blank">http://focus.ti.com/docs/prod/productfolder.jhtml?gene=
ricPartNumber=3DSN75240</A></FONT>
</P>

<P><FONT SIZE=3D2 FACE=3D"Courier New">Regards,</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Courier New">Thomas Fisher</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Courier New">Senior Systems Engineer</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Courier New">Texas Instruments, Inc. =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Business: 214 =
480-3736</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Courier New">P.O. Box 660199 MS8710&nbsp; =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
Fax:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 214 480-3160</FONT>
<BR><FONT SIZE=3D2 FACE=3D"Courier New">Dallas, TX =
75266-0199&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
[<U></U></FONT><U><FONT COLOR=3D"#0000FF" SIZE=3D2 FACE=3D"Courier =
New"><A =
HREF=3D"mailto:[email-masked]">mailto:[email-masked]</A></FONT></U><=
FONT SIZE=3D2 FACE=3D"Courier New">]</FONT>
</P>

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

End of ibis-users V1 #12
************************