RE: [IBIS-Users] Rising waveform, Fall waveform data tables


Subject: RE: [IBIS-Users] Rising waveform, Fall waveform data tables
From: Lynne Green (lgreen@cadence.com)
Date: Mon Aug 19 2002 - 13:02:23 PDT


Hello, Steven,

You are right that V-t tables make the model more accurate
than having just the [Ramp] values.

The IBIS specification does not describe how the tables are
to be used, so not all EDA tools use the tables in exactly the
same way. SpecctraQuest does use all of the V-t tables.

Two relevant papers available on the web:
http://www.mentor.com/icx/modeling/ibis_modeling.html#documents
1. "The Development of Analog SPICE Behavioral Model
Based on IBIS Model" - by Ying Wang and Han Ngee Tan,
Proceedings of the Ninth Great Lakes Symposium on VLSI,
(March 1999)
2. "Extraction of Transient Behavioral Model of Digital I/O
Buffers from IBIS" - by Peivand Tehrani,Yuzhe Chen and
Jiayuan Fang, 46th IEEE Electronic Components &
Technology Conference (May 28-31, 1996).

Best regards,
Lynne

Dr. Lynne Green
Senior Member of Consulting Staff
Cadence Design Systems, Inc.

"All the world's an analog stage, whereon digital plays bit parts."

-----Original Message-----
From: Steven_McKinney@Dell.com [mailto:Steven_McKinney@Dell.com]
Sent: Monday, August 19, 2002 12:23 PM
To: ibis-users@eda.org
Subject: [IBIS-Users] Rising waveform, Fall waveform data tables

Can anyone explain how the simulator uses the Rising/Falling waveform
data tables that are included in an IBIS model. Some models contain
several tables of data for the Rising/Falling waveform but it is unclear
how the simulator uses this information. Does the simulator select one
table depending on simulation conditions or does it interpolate across
all the tables? I know that the information is optional, but I am
assuming that in order to get more accurate simulation results, you
should have this waveform data. Thanks for any clarification!

Regards,

Steven McKinney

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