[SI-LIST] Re: IBIS Model Quality (or lack thereof)

Thanks everyone, for your contributions to this thread so far.  By way of
summary, we've heard from the following semiconductor companies:

- Intel
- Fairchild
- Serverworks

(if I left anyone out, my apologies)

... and I'll vouch for both Intel and Micron myself, both in terms of model
quality and support.

It is my strong suspicion that precious few IBIS models are validated in any
meaningful way before they are shipped to the customer.  A few of your have
expressed hopes for the IBIS model quality committee that has just gotten
started, I share your hopes and enthusiasm for the effort.

A number of you have outlined some of the testing processes you use, and I'd
like to suggest that we explore that subject a bit more.  We've spent a LOT
of time here lately correlating IBIS models to their HSpice counterparts.
We're currently using two "standard" text fixtures to compare IBIS/HSpice
models:

* I/O buffer connected to VDDQ/2 through 50 ohms
* I/O buffer connected to 0.5ns, 50ohm tline, 5pf to GND at tline end

The theory is that the first test fixture compares rising/falling edge
characteristics and buffer strength, while the second test models the
driver's response to a reflected wave (primarily the value of C_Comp).  If
you get the HSpice/IBIS buffers to agree across these two tests, chances are
the rest of the puzzle falls into place, provided you agree on things like
pin parasitics and switching thresholds.

So, I'm curious - for those of you who test IBIS models against any kind of
reference (HSpice or measurement) - what kinds of test loads are you using,
and what are you looking for?

As always, all input (on and off the list) is greatly appreciated.

Todd.

Todd Westerhoff
Signal Integrity Engineer
Hammerhead Networks
5 Federal Street - Billerica, MA - 01821
email:twester@xxxxxxxxxxx - ph: 978-671-5084
============================================

"I’m starting With the man in the mirror
 I’m asking him to change his ways
 And no message could have been any clearer
 If you wanna make the world a better place
 Take a look at yourself, and then make a change"


- "Man in the Mirror", Michael Jackson


------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages 
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

Other related posts: