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Old 02-22-2005, 06:15 PM
Austin Lesea
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Default Re: Issues with a batch of Virtex-II chips

All,

Igor has his case now submitted, and it was escalated due to its nature
(basically saying "lines down" makes that happen).

As of 8:30 AM PST 2/22/2005 here in San Jose we have folks on it.

Thanks to all who posted. For those interested, I will probably post
the results here (if Igor agrees) as there seems to be some interest in
lot related failures.

Generally speaking, lot related failures are almost always design
related: either the lot silicon is a little faster, or a little slower
(but within spec's) than the previous lot, and an unconstrained timing
path doesn't work. Sometimes IOs are a little stronger, or a little
weaker, and that too is within spec but makes a difference in a design.

The fabric speed was the case of the customer who designed their own
FIFO (and didn't understand schrnoization circuits), and "lot" related
problems.

In this case, we have just started, so Igor will learn failry quickly
what the differences are between the lots, and we will help resolve what
the cause of the problem is, and provide solutions.

Thanks again to all who have interest in this sort of posting, as it
gives us a chance to educate folks on the services we offer (the
hotline), the escalation procedures for hot cases (lines down), and the
nature of this particular kind of problem, and the types of likely
resolutions we often find.

In no way am I implying that Igor has a funny path in his design: I am
only suggesting that this is often our experience. Rarely (VERY RARELY)
we have lot quality problems, test escapes, etc. that all manufacturers
occasionally have when something doesn't go right in the test group. Of
course, each time that happens, it is cause for reviews of quality and
proceedures so we never make that mistake again!

So to all of you who think you might have a lot quality problem, again,
that is so rare that I only mention it here to be accurate and honest.

Often mentioning something in the news group is like describing a new
rare illness to a hypochondriac, suddenly everyone thinks they are sick
with the new rare disease!

(In which case it isn't rare anymore....)

Austin
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