Subject: Re: IBIS BIRD64 - Package Model Selector

From: [email-masked]
Date: Tue, 26 Oct 1999 16:20:12 -0400

Arpad,

The "[Package Model Selector]" keyword idea is great.  I agree 100% that
this is needed in the next generation IBIS (IBIS 4.0).

However, I do think that for the corner situations (TYP, MIN, MAX), we need
to have a different keyword or structure.  Or do we?  I am looking for some
discussion from the IBIS community on this matter.  Does it make sense to
use a "typical" package model for all three simulations (MIN, TYP, MAX)?
Does it make sense to use a MIN package model in a MAX simulation?

Regards,
Michael Cohen

IBM Personal Systems Group
Design Tools Department
D-26D/B-201/R-D104H
3039 Cornwallis Road
Research Triangle Park, NC 27709

Phone:  919-543-4042 (T/L 441-4042)
FAX:  919-543-8221 (T/L 441-8221)
Internet Address:   [email-masked]

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From: Scott McMorrow <[email-masked]>
Date: Tue, 26 Oct 1999 14:58:53 -0700

Michael and Arpad,

It certainly makes sense to perform multiple combinations
of simulations with Min/Max packages and device models.

Simulation corners are very interesting things.  Often the
least thought of combination gives the greatest problems.

Max I/V curves and Min package model would be useful
for hold time simulations, as also would Min I/V curves and
Min package.

regards,

scott

--
Scott McMorrow
Principal Engineer
SiQual, Signal Quality Engineering
18735 SW Boones Ferry Road
Tualatin, OR  97062-3090
(503) 885-1231
http://www.siqual.com

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From: Al Davis <[email-masked]>
Date: Tue, 26 Oct 1999 22:40:04 -0700

> Does it make sense to use a MIN package model in a MAX simulation?

Lots of combinations of typ/min/max make sense.  I suppose even a completely
arbitrary mix makes sense.  A simulator could do this now, without any changes
to the spec.  Current simulators are not exploiting nearly the capability that
the existing spec allows.  Desiging a reasonable user interface would be a real
challenge.  Let's leave the spec alone, and let the simulator makers figure out
how to do it.

I am confused by the comment about an "alternate syntax".

It is not clear from the spec how this is placed within the file.  Logically,
it can only go at top level.  I suppose this would be implicitly stated by the
position in the spec.