RE: [IBIS] IBIS-ISS Package Modeling Status/Overview

Arpad,

I refer to my comment "IBIS has sufficient resource to accomplish this
task."

If you think that you can come up with a syntax for IBIS that satisfies
all of the Levels I describe (so that it can get into IBIS 6.0) then
please do.

Walter

From: owner-ibis@eda.org [mailto:owner-ibis@eda.org] On Behalf Of Muranyi,
Arpad
Sent: Thursday, July 19, 2012 1:07 PM
To: ibis@eda.org
Subject: RE: [IBIS] IBIS-ISS Package Modeling Status/Overview

Walter,

In my opinion, we should not have to deal with any of these

distinctions in a specification. The specification should

have the means to define the pins/balls, pads/bumps, on-die

nodes around the buffer and anywhere else, and provide a

mechanism to place an IBIS-ISS subcircuit between any of

these points.

Whether this IBIS-ISS subcircuit has a single ended line or

multiple differential channels in it, or whether it is signal

or power, coupled or uncoupled, high frequency or low frequency

makes no difference. Either one of these need nodes to be

connected to and that's it. I would just like to find a good

syntax to define the nodes and how the IBIS-ISS subcircuits are

instantiated and connected to these nodes, and be done. The

rest should be up to the model maker.

As soon as we put problem specific solutions into the specification

we submit ourselves to limitations and rigidity in the spec, which

IBIS is famous for. As you know it full well, it takes a lot of

time to make changes to the specification, and if we put such

limited capabilities into the spec, we will be forced to start making

changes to the spec as soon as it is released.

In this case it would not make a big difference to define a more

general syntax right now than take incremental baby steps with

limited functionalities. This stuff is really not all that complicated.

Thanks,

Arpad

=========================================================================

From: owner-ibis@eda.org [mailto:owner-ibis@eda.org] On Behalf Of Walter
Katz
Sent: Thursday, July 19, 2012 11:20 AM
To: ibis@eda.org
Subject: [IBIS] IBIS-ISS Package Modeling Status/Overview

All,

This e-mail is a summary of applying IBIS-ISS to IBIS package modeling for
IBIS 6.0. This summary is based on discussions in IBIS-ATM, and private
communications with Brad Brim, Arpad Muranyi, Michael Mirmak and various
IC Vendors.

Definitions:

Pin The connection point of a package model to a
board.

Pad The connection point of a package model to the
die.

Channel Either a single ended connection between a single
Pin and a single Pad, or a differential connection between two Pins and
two Pads.

Finally, I will describe the package modeling solution for several Levels
of package model complexity.

Level 1

Package models for a single Channel without coupling to either Power or
other Channels.

Useful to have multiple Channels point to the same IBIS-ISS subckt,
passing a unique Length for each Channel.

Important to have more than 3 corners.

Level 2

Package models for a single Victim Channel with coupling to other
Aggressor Channels in the same bus but without coupling to Power.

Useful to have multiple Channels point to the same IBIS-ISS subckt,
passing a unique Length for each Channel.

This assumes that the Aggressor Channels have the same length as the
Channel.

Important to have more than 3 corners.

Level 3

Package models for a multiple Channels with coupling between them but
without coupling to Power.

Channels may be in multiple buses

Package model may be for complete package or for a slice of the package..

Level 4

Package models for Power and Ground.

No coupling to Channels.

May require multiple Pads for the Power and Ground Nodes.

In general there will be a different number of Pads and Pins

Level 5

Package models for a multiple Channels, Power and Ground with coupling
between Channels and between Channel and Power.

Channels may be in multiple buses.

Package model may be for complete package or for a slice of the package.

Recommendations:

I recommend that IBIS 6.0 should fully address Level 1 and Level 2 for the
following reasons:

IBIS has sufficient resource to accomplish this task.

Gives package information to Users/EDA tools to enable users to make
engineering decisions.

Is in accordance with many industry standards package model
specifications.

I recommend that IBIS 6.0 should be enhanced to enable EDA tools to uses
Level 3, 4 and 5 models that publish their connections ports with
something like MCP.

Walter

Walter Katz

wkatz@sisoft.com

Phone 303.449-2308

Mobile 303.335-6156

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Received on Thu Jul 19 10:22:37 2012