RE: [IBIS-Users] V-t tables generation

Ramiro,

Theoretically it shouldn't matter.  The reason is because
the I/O buffer model should have enough pre-drivers before
the output stage so that the input to the first pre-driver
should not effect the output of the final stage.

For this reason I would recommend that you should apply 
the fastest edge possible, because the Vt curves must be
time correlated, and due to the input threshold voltage
variations between rising and falling edge inputs, the
faster the stimulus is, the better your time correlation
will be.

Arpad Muranyi
Intel Corporation
----------------------------------------------------------

-----Original Message-----
From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On Behalf Of RODRIGUEZ_LECONA_RAMIRO
Sent: Monday, March 28, 2005 1:36 PM
To: ibis-info@eda.org; ibis-users@eda.org
Subject: [IBIS-Users] V-t tables generation


  Hi all, 

     When I generate the V-t tables for an output IBIS model I have to apply 
a transition in its input. If the datasheet specify an output rise/fall time 
range between, for example, 0.1ns min and 1.0 ns max, What is the rise/fall 
time I have to apply to the input transition? How do the IBIS simulators 
implement the rising/falling waveforms when the IBIS model was generated 
with a rise/fall time smaller than the the rise/fall time used to switch the 
buffer? 

     Regards, 

     Ramiro

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