RE: [IBIS-Users] Capacitance and transition time

Within reason he should be able to get good results.  Whenever an IBIS model
is used to simulate a system the board will have parasitic capacitances on
it.  So the models are supposed to work with the simulator to get reasonable
results.  But I would not try to load the device with 10uF and expect to get
good results.

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@eda.org [mailto:owner-ibis-users@eda.org]On
Behalf Of Michael Sachtjen
Sent: Monday, January 30, 2006 11:24 AM
To: IBIS-USERS
Subject: [IBIS-Users] Capacitance and transition time


A coworker wants to simulate what affect connecting
different capacitors to the output pin of a device
would have on its transtion time.  He doesn't have
access to spice models and he asked me if he could use
IBIS models.  I told him that since the models are
characterized under a given load, changing that load
in simulation may not give him very accurate results.
Was I correct, or will the simulator use the values of
the IV curves and test fixture to accurately skew the
rise and fall times specified in the VT curves?

Thanks in advance,

Mike Sachtjen

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