Subject: Voltage Reference Pins

From: "Fisher, Thomas" <[email-masked]>
Date: Thu, 7 Dec 2000 12:05:10 -0600

Looking through the latest IBIS version I don't see any provision for pin(s)
that are used simply as a voltage reference.  Having said that, do we still
model these pins?  If so, how are they treated?  Thanks.

Regards,
Thomas Fisher

---

From: Bob Ross <[email-masked]>
Date: Thu, 07 Dec 2000 10:32:57 -0800

Tom:

You are correct that IBIS Version 3.2 does not model the
reference voltage pins directly.

BIRD62.6 covers internal and external reference voltage
specification and interactions with other parameters.  So the
modeling effects will be covered in more detail in a future
version of IBIS.

For existing Version 3.2 models, I recommend that you designate
the reference voltage pins as NC or as POWER pins and capture
the reference voltage variations and threshold variations
with the [Voltage Range] or [Pullup Reference] keywords 
threshold subparameters.

Bob Ross
Mentor Graphics