[SI-LIST] Re: IBIS Model Quality (or lack thereof)
- From: Dave Macemon <davem@xxxxxxxxxx>
- To: twester@xxxxxxxxxxx, <si-list@xxxxxxxxxxxxx>
- Date: Tue, 26 Mar 2002 15:34:21 -0800
Todd and all,
As for the quality of IBIS models, SiQual agrees that there are major
problems.
SiQual presented a paper at DesignCon 2002 that were the results of
research we did into the quality of IBIS models on the web. We gathered
all the IBIS models we could find (Well, actually all the models a BOT
could find, over 4500), and found that 20% of the files had at least one
significant error or significant warning.
The complete paper and presentation can be found at:
http://www.siqual.com/publications/index.html
the paper is titled
Critique of IBIS Models Available on the Web
regards
davem
At 05:55 PM 3/26/2002 -0500, Todd Westerhoff wrote:
>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
>
>
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===
Dave Macemon
SiQual, A division of Stilwell Baker
davem@xxxxxxxxxx
phone (503)885-1231
fax (503)885-0550
http://www.siqual.com/
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