New package model proposal by Steven Peters

Hi,

I want to put in a word as an IBIS model user. First, I must admit that I haven't
reviewed Steven's Egg carefully. I have only scanned it cursorily.

I don't believe that anyone would seriously propose providing IBIS models that are
package dependent. Package information is desireable to the user. The more the
better as long as it can be separated from the die information if necessary.

Am I wrong in thinking that some of the more complex packages like 200+ pin BGAs
and PGAs are actualy circuit boards? If they are, then there are a lot of
similarities with SIMMs.

If Steven's Egg will allow manufacturers to provide package information for SIMMs,
I want to nominate him for IBISian of the year, even if that wasn't his intention.
If the Egg won't allow for that level of package information, why not make it so
that it will (provided the user can separate die and package information when
necessary).

It may be difficult or impossible for anyone to convince SIMM manufacturers to
provide SIMM package information, but I would like to leave the door open for them
to do so.

I suspect that packaging information will become more and more important with time
and that packaging will become more complex rather than less. Please keep the IBIS
standard open to the future.

Regards,
Fred Vance
FirePower Systems, Inc.

Begin forwarded message:

To: Ibis@vhdl.org
Subject: Re[2]: New package model proposal by Steven Peters
Date: Wed, 10 May 1995 09:26:09 -0700
From: Stephen Peters <speters@ichips.intel.com>

Hello Chris, Kumar, Kellee and others:

  On 5/9 Chris Reed wrote:

>The problem as I see it is that the Egg proposes one way to model
>an MCM which may do for some particular part, but may be inadequate for
>some other part. We do not want to add to Ibis a plethora of syntaxes
>to support many different package model options.

     My proposal was never intended to model MCMs, SIMs, etc. and I belive
we should take a long, hard look before we start trying to describe
what amounts to complex circuit boards. IBIS is a standard describing
*I/O buffers*; we are concerned about the packaging only is as much as
its effects are inseperable from the actual silicon characteristics.
Also, this proposal is an attempt to refine what has already been defined,
not come up with a whole new scheme. It does cover existing DIP/SOIC/
PQFP/BGA/PGA/TAB packages -- basicly any package where the leadframe
can be represented as multipule elements in series, with coupling between
any set of arbitary elements.
    This may be a bit of a philosophical discussion, but consider this:
users, given half a chance, would take a '.pkg' file that allows general
descriptions and use it to describe an entire motherboards net topology.

This may be a 'great and wonderful' thing, but is that the intent of IBIS?

         Regards,
         Stephen Peters
Received on Wed May 10 10:40:59 1995