Re: using s2ibis2

Betty,

Not sure if you got any responses to your questions. My 2cents below:

> Hello,
>
> I have 2 questions regarding s2ibis2:
>
> 1) In the email sent by Dan Aleksandrowicz on Aug 13, 2000, he said that there
is a version of s2ibis sofware that increases the resolution to 4 decimal
places. I recently downloaded s2ibis2 version 1.1 from the IBIS homepage, and
the accuracy that I get is 2 decimal places. Where can I get this fix for the 4
decimal place resolution?

You can find this 'fix' version at:
http://www.eda.org/pub/ibis/s2ibis/s2ibis2_v1.1/

Download the file called: s2ibis2_fix.tar.Z
Read the '00readme.txt' file for details after uncompressing and untar'ing.

>
> 2) I encountered a DC convergence problem when I was using s2ibis2 to generate
an IBIS model for a 3-state Output pad (using HSPICE). So, I manually changed
the spice file generated by s2ibis2 for the pulldown curve to sweep from 6.6V to
-3.3V in intervals of -0.1V (instead of its default from -3.3V to 6.6V in
intervals of 0.1V). In the resultant .ibs file, I don't think I'm getting the
correct pulldown curve with the subtraction of the gnd clamp curve. Is this
because for s2ibis2 to generate the data correctly, the voltage values in the
output file have to be increasing? Any ideas on other workarounds?
>
> Many thanks,

The pulldown curve from s2ibis2 does not subtract the gnd clamp. This is very
visible if you plot the data points. I am unable to comment further since I do
not know how your generated .ibs file looks like. Sometimes, I would reduce the
sweep range to get away from convergence issues. Then I could extrapolate the
end data points to the IBIS specified ranges(this is a valid approach).

Regards,
Syed
Cisco Systems, Inc

 
Received on Tue Sep 19 22:33:48 2000