Subject: RE: IBIS Model question

From: "Dagostino, Tom" <[email-masked]>
Date: Mon, 23 Apr 2001 13:15:11 -0700

From the IBIS 3.2 spec
 
BM__Toc460058252| Keyword: [Ramp]

| Required: Yes, except for inputs, terminators, Series and Series_switch

| model types.

| Description: Defines the rise and fall times of a buffer. The ramp rate

| does not include packaging but does include the effects of the

| C_comp parameter.

| Sub-Params: dV/dt_r, dV/dt_f, R_load

| Usage Rules: The rise and fall time is defined as the time it takes the

| output to go from 20% to 80% of its final value. The ramp

| rate is defined as:

|

| dV 20% to 80% voltage swing

| -- = ----------------------------------------

| dt Time it takes to swing the above voltage

|

| The ramp rate must be specified as an explicit fraction and

| must not be reduced. The [Ramp] values can use "NA" for the

| min and max values only. The R_load subparameter is optional

| if the default 50 ohm load is used. The R_load subparameter

| is required if a non-standard load is used.

|---------------------------------------------------------------------------
--

[Ramp]

| variable typ min max

dV/dt_r 2.20/1.06n 1.92/1.28n 2.49/650p

dV/dt_f 2.46/1.21n 2.21/1.54n 2.70/770p

R_load = 300ohms

Tom Dagostino 
IBIS and Tau Modeling Manager 
SDD 
Mentor Graphics Corp. 
503-685-1613 
[email-masked] 

-----Original Message-----
From: Abdulrahman Rafiq [mailto:[email-masked]]
Sent: Monday, April 23, 2001 1:07 PM
To: Mathew, Elizabeth (MED)
Cc: [email-masked]
Subject: Re: IBIS Model question

dv/dt_r : seems like its a propogation velocity/ actually acceleration--it
might be the rise time . However I am not sure. 

"Mathew, Elizabeth (MED)" wrote: 

Hi IBIS Gurus, 
                     In the IBIS model of any part does the term 
"dv/dt_r" correspond to the rise time (tr - as denoted in the datasheet) 
of that particular part? 
Thanks, 
Elizabeth 

Elizabeth Mathew 
Signal Integrity Expert, 
Global Electrical Technology Center, 
GE Medical Systems, 
Phone:(262)544-3776 
Fax:(262)548-2315 
< mailto:[email-masked] <mailto:[email-masked]> >

-- 

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CISCO SYSTEMS INC.

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