Subject: [IBIS-Users] Vinh for Differential Part
From: Timothy Coyle (Timothy.Coyle@nsc.com)
Date: Fri Dec 06 2002 - 04:59:10 PST
Hello,
I have a differential device in an IBIS file. I define a Vdiff of 100mV
for my differential signal thresholds. However, I also have to define a
Vinh and Vinl
for the single-ended positive and negative differential Input model types
in IBIS. The IBIS spec (3.2) states that:
If a pin is a differential input pin, the differential input
| threshold (vdiff) overrides and supersedes the need for Vinh
| and Vinl.
However, if I do not define a Vinh and Vinl for my differential inputs,
then the IBIS parser gives me a warning. It also seems that some
simulators use this
Vinh and Vinl for the single-ended differential signals. If this is an LVDS
input, switching from 1 to 1.4 V, then I could put thresholds of 1.1 and
1.3?
I'm curious as to what other people do and why the parser gives me this
warning?
Regards,
Tim
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