Re: IBIS model enable signals


Subject: Re: IBIS model enable signals
From: Ingraham, Andrew (Andrew.Ingraham@compaq.com)
Date: Tue Jan 08 2002 - 10:19:25 PST


> Is it possible to add a control that the IBIS model takes into
> account
> during the simulation.
> e.g. - an enable signal that makes the pad 5v tolerant instead of 3v
> tolerant?
 
I would think that you probably would not need to change a model
on-the-fly "at speed." That is, either the device operates in one mode
or the other, or it gets changed slowly when little else is going on.

So you could have two different models, one for each mode.

If someone happens to have a circuit that uses the device in both modes,
he could simulate each mode separately.

For some ICs that are usable both ways, the output drivers do not
change, but the overshoot clamp does (by way of connecting certain power
pins to 5V or to 3.3V). Thus, [Power Clamp Reference] could be set to
one voltage or the other, with few if any other changes to the model.

Regards,
Andy



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