Multiple Timing Formats and Ibis

Hello,

It seems to me the point Ron Christopher raises about multiple
dies in one MCM is significant from a timing point of view,
but is not significant for Ibis with its current charter.

From an Ibis viewpoint an MCM is just another package with
a certain set of driver, receiver, power, and ground pins.
The particular construction inside the package is not of
interest except in how it affects the package model (particularly
with the Bird 28 changes).

From a timing viewpoint it seems to me we must take a similar
stand. There is no hope of capturing all possible intricacies
of an MCM layout in some standard description language. That is
the function of the layout tool vendors and the associated analysis
vendors. Many MCMs today are simple, but there is no fundamental
restriction on their structure. They could become as complicated
as a board.

So, while Ron raises some important issues, I don't think this
is the right forum to address those issues. Ibis should stay
focused on a package level description regardless of the internals
of the package. From a timing perspective (which is off the thrust
of Ibis) composite packages such as MCM's will require timing models
that descirbe their behavior as a whole.

Christopher Reid
chris@icx.com
503-603-2527
Received on Mon Sep 18 08:57:44 1995