RE: [IBIS] Question regarding V-t tables

Andy,

You are correct. And your last paragraph is exactly what I
am trying to address with this discussion. It seems that we
could do it with a few more subparameters under the waveform
keywords using the old IBIS syntax.

However, it is also true that we could do this with *-AMS
without touching the old IBIS spec, so part of the question
revolves around whether this is a useful idea or not.

On the other hand, since the old IBIS spec does not prevent
us from repeated Rfixture Vfixture parameters, I also wonder
whether we need to impose a (clarification) rule to disallow
that in case we decided not to add this capability to the old
waveform syntax.

Arpad
==============================================================

-----Original Message-----
From: owner-ibis@eda.org [mailto:owner-ibis@eda.org] On Behalf Of Andrew Ingraham
Sent: Thursday, September 09, 2004 6:31 AM
To: ibis@eda.org
Subject: Re: [IBIS] Question regarding V-t tables

Arpad,

In the example you showed on page 34, it looks like that was just a case
where the inverting and non-inverting pads were not the same electrically
(at least not in the time domain), but were being represented by the same
IBIS data. Not exactly what I would call a data dependency, though you
might think of it that way because it coincidentally manifests itself as a
rising/falling drive difference.

A good example of a data dependent buffer would be one with pre-emphasis (or
pre-distortion or pre-equalization) of some sort, especially using digital
pre-emphasis based on previous input states.

I think that is the kind of device that would benefit from multiple V-t
tables for the same V_fixture and R_fixture conditions. (Otherwise it can't
be done with IBIS, can it? But I have not kept up very well with recent
IBIS developments.)

Regards,
Andy

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Received on Thu Sep 9 09:50:53 2004