Re: Virtex4 burn-in failure


<msn444@xxxxxxxxx> wrote in message
news:c7463bc7-1443-4ee1-9de6-5b602825bb8e@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hello,

I've observed a failure of one of our Virtex4-based products that is a
bit puzzling. The device had been in operation for several weeks
before failing, and is among a run of a couple hundred. I've dissected
the specimen, and the Virtex4 appears to draw a large amount of
current and gets hot immediately upon power-up. It does not configure
or show any signs of life.

Aside from the possibility of this being induced by a manufacturing
defect that took its time to show up, can anyone think of any design-
related causes of a failure like this?

Thanks in advance,

Mike.

Do any of the power supplies EVER exceed the maximum allowed? You should
carefully check power-on, operating, and power-off conditions with a high
speed scope. This is the only thing that I've ever done that truly damaged
an FPGA.

Another (less likely) possiblility is overcurrent on inputs due to driving
them above and/or below the supplies.

What about over-temperature? However, it would have to get effing hot (>125C
?).

I can't think of anything that would bother the thing.

Bob


.

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