3-state pullup table generation by s2ibis2 0.91BETA

Hello IBIS users:

We at Mitsubishi have evaluated the new version of s2ibis2 v1.0,
and we're quite please with the new features and good documentation.
Thank you to the IBIS developers at NCSU.

A couple of tests were run with s2ibis2 version 1.0 and 0.91BETA on the
same device. We observed the results and thought that there is a problem
in 0.91BETA version regarding pullup table generation for 3-state pin.

To generate the Pullup table for 3-state pin, 0.91BETA version subtracts
the pullup disable curve from the pullup enable curve for the entire
sweep range [-Vcc to 2*Vcc]. While the correct subtraction should be
in the pullup disable range [Vcc to 2*Vcc], which is the same as the
Power Clamp range. Such operation executes properly in the new version 1.0.

We had provided numerous models generated by 0.91BETA version to customers.
I wonder if other IBIS users and model providers experience a similar problem.
Although 0.91BETA is just a beta version, I feel that all 3-state models
generated by 0.91BETA should be re-run using the latest s2ibis2 version 1.0
to meet IBIS SPEC. This may take a while if you have to re-do a lot of models.
I will be glad to hear your ideas/comments on this, as well as how servere the
impact of the bug on IBIS simulators you're using.

Best regards,

Hoang Nguyen

 
Received on Tue Feb 11 09:23:10 1997