Re: [SI-LIST] : Bad IBIS models!

About this list Date view Thread view Subject view Author view

From: Brian Young (briany@ibmoto.com)
Date: Wed Mar 15 2000 - 15:42:47 PST


I can't vouch for what goes on in other companies or even
my own. I see a very small part of a very large operation
in a very large industry. Probably everyone is in just
about the same boat, so making something happen is tough.

With that disclaimer, then ...

The generation and supply of consistently good IBIS models
across the product line is quite an expensive proposition.
It requires regular training, because I/O designers come
and go, software, hardware validation, cataloging, maintenance,
etc. The effort must span multiple organizations and
geographic regions. A high-level effort would be required
with significant funding (i.e. millions). Without such
an effort, what you get are individual best efforts.

The people who can make this happen do not read this list.
How do you convince them to expend the resources to make
consistently good IBIS models available to customers?
You can't just say, "A bunch of people on the SI-LIST bitterly
complain about the quality of IBIS models, and if we don't
do something about it, we will lose sales."

Any ideas?

Brian

Kim Helliwell wrote:
>
> Are any component vendors reading this list? I'm frustrated
> with some of the excuses for IBIS models some of them
> (naming no names) distribute on the web and elsewhere.
>
> Here are the problems I've seen so far:
>
> 1. Models that don't have a complete pin map
> 2. Pin map does not match the data sheet.
> 3. Files that specify all the pins, but some of the models referenced
> don't exist in the file
> 4. Driver models that don't have any rise and fall curves.
> 5. dv/dt values that are *GIVEN* as 0.00000/0.00000.
> (This is totally unacceptable by my signal integrity tools)
> 6. dv/dt values that are *GIVEN* as -x.xxxx/y.yyyy
> (that is, negative values specified; also not accepted by
> my SI tools)
> 7. Min/Typ/Max values or curves that are scrambled
> ( Typ > Max, Min > Typ, Min > Max)
> 8. VI and clamp curves that are discontinuous.
>
> My word to vendors: customers that use IBIS models are not that
> easily fooled. We use ibischk3, we look at the curves with a graphing
> utility, and we have conversion programs that choke on one or more
> of these problems. We can look at a model and pretty quickly tell
> whether it is a good or a bad one. And it's pretty clear over time
> which vendors consistently provide good models, and which ones obviously
> aren't interested in providing good models and consequently do a
> half-assed job on them.
>
> We're watching, and we know who you are!
>
> Of course, vendors that don't supply models at all don't
> even rate this much attention.
>
> OK, I feel better now. Anyone else?
>
> --
> Kim Helliwell
> Senior CAE Engineer
> Acuson Corporation
> Phone: 650 694 5030 FAX: 650 943 7260
>
> **** To unsubscribe from si-list or si-list-digest: send e-mail to majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE si-list or UNSUBSCRIBE si-list-digest, for more help, put HELP.
> si-list archives are accessible at http://www.qsl.net/wb6tpu
> ****

-- 
***************************************************************
* Brian Young                           phone: (512) 996-6099 *
* Somerset Design Center                  fax: (512) 996-7434 *
* Motorola, Austin, TX               brian.young@motorola.com *
***************************************************************

**** To unsubscribe from si-list or si-list-digest: send e-mail to majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE si-list or UNSUBSCRIBE si-list-digest, for more help, put HELP. si-list archives are accessible at http://www.qsl.net/wb6tpu ****


About this list Date view Thread view Subject view Author view

This archive was generated by hypermail 2b29 : Thu Apr 20 2000 - 11:35:38 PDT