RE: [IBIS] BIRD95: Power Integrity Analysis Using IBIS

Mike, Thanks for your comments, some of my responses in-line - Syed

On Fri, 2005-01-07 at 10:57, Mike LaBonte wrote:

>
> 4) Note that some of the debate relates to assumptions about what circuitry
> is inside the black box SPICE model. This BIRD gives us a forum for
> discussing those assumptions, but any effective change in requirements for
> what is included or not included in SPICE buffer models today probably
> presents a barrier to production of models using this keyword. It would help
> me if the diagram in BIRD95 drew a box around the portion that constitutes
> the black box buffer, with now-familiar 7 terminals at the perimeter.
>

As stated in the Jan7th teleconferences, we are working with encrypted
SPICE models and as such visibility into the black box is very
difficult. That will *not* cause a serious barrier to the keyword as you
indicate. The currents considered are *composite* in nature. There are
boundaries we are limited to in working with encrypted models.
Regardless, as we mentioned, we will draw a box around the diagram and
highlight the ports of concern.

> 5) Why is it called [Series Composite Current]? If this is the series
> current into the power port of the buffer what would be called the shunt
> current? Inside the buffer we might regard this current as a composite of
> pullup, predriver, and various capacitance currents. But treating the buffer
> as a black box, isn't there only one I/O (excluding clamp) power terminal?
> Could we call it [Power Current]? That would also make for a neater syntax
> if there ever is a [Ground Current] keyword.
>

The first version of the BIRD was using Series Pin Mapping to show how
the PWR GND nodes are connected etc and as such we wanted a new keyword
for the IvsT to have some relation to that. So the name [Series
Composite Current]. We will wait further before making more changes to
keyword names.

> I would also like to suggest that that comments of those developing IBIS
> simulators that perform PDS analysis today would be especially helpful in
> this important effort.

Very good comment. We do want more EDA participation so get insights
into how this could be used, tool specific limitations, algorithm issues
etc as it pertains to BIRD95. There are also EDA vendors who are
actively engaged on working on this BIRD95.

Regards,
Syed

-- 
IBIS Vice-Chair & Webmaster
Cisco Systems, Inc
> -----Original Message-----
> From: owner-ibis@eda.org [mailto:owner-ibis@eda.org] On Behalf Of Mirmak,
> Michael
> Sent: Saturday, December 25, 2004 1:59 AM
> To: ibis@eda.org; ibis-users@eda.org
> Subject: [IBIS] BIRD95: Power Integrity Analysis Using IBIS
> 
> 
> The enclosed BIRD, Power Integrity Analysis Using IBIS, is submitted on
> behalf of Syed Huq, Vinu Arumugham and Zhiping Yang of Cisco Systems.
> It will be discussed at the January 7, 2005 IBIS Open Forum teleconference.
> 
> - Michael Mirmak
>   Intel Corp.
>   Chair, EIA IBIS Open Forum
> 
> 
> 
> 
> 
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