Subject: problems with s2ibis2 v1.0 ?

From: [email-masked] (Cornelia Foss)
Date: Fri, 21 Feb 97 15:17:30 +0100

Hello everyone,

first of all I'd like to thank Arpad Muranyi who explained a good method
to avoid double counting when modelling some certain inputs.
However, I think the parser should give a warning if the GND_ and POWER_
clamp tables define currents for the same output voltage and both
tables contain non-sero values within this overlap area. This is currently
mandatory within IBIS for GND_clamp at Vcc and POWER_clamp at 0V define
two currents for the same voltage.

I would be very grateful if anyone could help me with s2ibis2 v1.0.
The main problem is that s2ibis2 does not subtract the POWER_clamp
data from pulldown curves of I/Os (the same with GND_clamp and pullup)
that resulting pulldown tables that contain diode current for Vout
greater than Vcc. (same problem with 3-state type drivers)
This would be correct if simulators add only ONE clamp table to the pullup/
pulldown tables to get the total I/V curve, but my spec says that both clamps
are constantly present and appropriate pullup/pulldown tables are only
added when needed.

s2ibis2 is my favorite IBIS maker tool and works very well in version 1.0
so any help as well as comments on s2ibis2 v1.0 and clamp overlap is
very much appreciated. (and needed)

Sascha Pawel

email: [email-masked]