RE: [IBIS-Users] Multi Power Buses IBIS models.


Subject: RE: [IBIS-Users] Multi Power Buses IBIS models.
From: Mohan, Prabhu (Prabhu.Mohan@actel.com)
Date: Thu Aug 22 2002 - 15:05:15 PDT


Hi Anshuli,

Vil & Vih are required for any buffer that can be an output.
        - these are used only by s2ibis2 as stimulus for HSPICE simulation
        - they don't appear in the IBIS model

vinl & vinh are required for any buffer that can be an input (3-state is an
exception i think).
        - these are not used by s2ibis2 for HSPICE simulation
        - they do appear in the IBIS model (s2ibis2 just pastes the given
value)
        - these are the low and high input threshold voltages (eg. 0.8 and
2.0 for TTL)
          and are used by board level simulators

Regards
Prabhu/~

-----Original Message-----
From: Anshuli Goel [mailto:anshuli@india.ti.com]
Sent: Thursday, August 22, 2002 4:06 AM
To: ibis-users@eda.org
Subject: [IBIS-Users] Multi Power Buses IBIS models.

Hi

I am trying to generate the IBIS model for input model with multiple VDD
and VSS supply.I have in by ckt 2 VDDs and 2VSS.One VDD operates at 3.3 and
another at 1.8.The circuitry that is in direct contact with outside world
is working at 3.3 Volt while other circuitry is working on 1.8 V . As there
is no option to model these multi power buses in s2ibis2 utility . What
should I do to eliminate this problem.?

One more thing is Vinl and Vinh parameter must for input model to be
supplied in s2ibis2 utility ?

What is the difference in vinl,vinh and Vil and Vih . ? Where and how
these parameters should be used ?

If anybody can answer my querries that will be really helpful. ?

  Regards
  Anshuli Goel
  Texas Instruments

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