Subject: RE: [IBIS-Users] Temperature Range:
From: Ingraham, Andrew (Andrew.Ingraham@compaq.com)
Date: Thu Mar 28 2002 - 10:04:50 PST
> That doesn't make sense. The only place it is actually used in
> calculations in transit time, when [TTpower] or [TTgnd] keywords are
> used. These define the nonlinear capacitance in parallel with the
> clamps. High temperature is always low capacitance, therefore "fast".
But high temperature also means higher channel resistance, therefore "slow".
Whether or not an IBIS model actually makes use of the [Temperature Range] numbers themselves, is another matter, however. (Aside from the [TTpower] or [TTgnd] cases you mentioned.) There is plenty of data in an IBIS data sheet ("model") that may not be used by the simulator. Most implementation details are left as an exercise for the simulator vendor.
It is conceivable, if not entirely practical, that a smart simulator might select the appropriate device strength/speed (or interpolate between them), based on the desired simulation temperature. Or a simulator might give the user a message that the pairing he has selected (CMOS max strength devices simulated at max temperature) is impractical, so results would be overly conservative compared to the models.
Andy
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