DIYbanter - View Single Post - Failure of component that seems to incorrectly marked.

wrote:
Our end customer is seeing failures of a intersil 82c87 Octal inverting
transceiver which is behaving like a non inverting transceiver (82c86).
We have opened up the component and the die is marked 82C86. The part
may have been marked incorrectly,rebadged or is counterfeit. Has anyone
else encountered this or can recommend a way of detecting counterfeit
components?

M Talbot

Did you purchase these parts through authorized distribution channels
("disty") or did you get them through a broker? If they came through a
disty then you won't have a rebranded or counterfeit part. It could be
that it's either mismarked (a rare event), or possibly that that the
C86 and the C87 share a common die that has wirebonding options to
manufacture either version. You can answer that by decapping a known
good C87 from an old board and check the die in that. I'd also snap
pictures of the labels on the reels/tubes, the IC package, and the die
ID info, and send them to the Intersil rep and get the factory to give
a thumbs up or down on their validity. If they're from a broker, don't
expect much factory support or sympathy for your problem. Many
manufacturers just don't have the resources or finances to research
every non-disty part that is marked as theirs. Oftentimes they'll just
put up a generic notice on their website that there are counterfeits
out there, and encourage customers to use authorized channels.

If it is a broker part then rebranding and/or counterfeit is always a
possibility. Rebranding requires removing the old markings, which means
the part has to have been sanded or chemically treated prior to putting
on the new markings. Get a good look under a 10X-40X microscope and
look for signs of sanding, grinding or even old faded letters. I
looked on the Intersil site and this is a ceramic package, right? So
any sanding/grinding is likely to leave a roughened surface when
compared to a known good part. I've seen plastic packages that had to
be sanded so much to remove previous deep laser markings, that the tops
of the bondwires poked through the depressions in the rebranding laser
markings. In rare cases you may find that the sanding has thinned the
plastic package to the point where it no longer meets the minimum
thickness published in the package's mechanical specs. Other things to
look for when inspecting potentially risky parts are the presence of
flux residues - a sign that the part may have been reclaimed &
retinned, coplanarity defects, mixed lotcodes & datecodes in the trays,
wrong size pockets in the reels, substrate differences in BGAs -
especially within the same or close lotcodes. A curve tracer is real
handy to compare suspect parts with known good ones. If you have an
x-ray available, it's a great tool. You can quickly check and compare
die size, leadframe, and bondwire patterns.