Subject: Re: Questions re: [Rising Waveform], [Falling Waveform]

From: Jon Powell <[email-masked]>
Date: Mon, 05 May 1997 08:48:28 -0700

My recommendations differ a little from Kelle's, no doubt they are
simulator specific and you should seek a set that meet as many as
possible:

1) VT tables are absolutely necessary if the part is RISE TIME CONTROL
or SLEW RATE CONTROL

2) 1 VT table does not give much more information that simple rise time
and fall time (except as a golden waveform standard).

3) The loads used to generate the VT tables are technology dependent.
For most CMOS components the 50ohm to VCC, 50 ohm to GND are in the
right range.

4) Whether or not the VT tables make the model more accurate is
dependent on the technology of the driver. I suggest you try some
simulations with some representative simulators and see if the accuracy
meets your needs.

regards and happy ibising
Jon Powell
Senior Scientist, Viewlogic/Quad Design