RE: [IBIS-Users] Sweep voltage listing query

From: Tom Dagostino <tom_at_.....> Date: Wed Apr 19 2006 - 09:14:22 PDT · This archive was generated by hypermail 2.1.8 : Wed Apr 19 2006 - 09:15:39 PDT

Andy

My practice has been to make multiple models of the device each centered
around commonly found voltages such as in your example.  I use a model
selector to allow the user to select the voltage of interest in their
application.  I use the typical voltage in each of the individual models as
the basis for the sweep extremes.

Tom Dagostino
Teraspeed(R) Labs
13610 SW Harness Lane
Beaverton, OR 97008
503-430-1065
tom@teraspeed.com
www.teraspeed.com

Teraspeed Consulting Group LLC
121 North River Drive
Narragansett, RI 02882
401-284-1827

-----Original Message-----
From: owner-ibis-users@server.eda.org
[mailto:owner-ibis-users@server.eda.org]On Behalf Of Andrew Ingraham
Sent: Wednesday, April 19, 2006 5:22 AM
To: ibis-users@server.eda.org
Subject: Re: [IBIS-Users] Sweep voltage listing query

What would happen with a model of an IC with a very wide voltage range, say
for Vcc from 1.0 V to 3.6 V or more?

For such a part, it may be better to create separate IBIS models for the
different intended ranges; such as, one model for 1.5 V nominal, another for
2.5 V, another for 3.3 V, etc.  But if you had a single model that worked
well for the entire range (though it is debatable if you could make an
accurate IBIS model to do this), what should it use for its sweep range?
Probably not a Vcc in the middle of the range.

Are devices tending to have greater relative Vcc voltage ranges?  Many 5 V
parts were +/- 5% only.  Today's lower voltage parts have wider relative Vcc
ranges.  Perhaps IBIS needs to pay closer attention.

Just a thought....

Andy

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