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
Have you contacted Intersil? Mistakes do happen.
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I haven't seen this happen before, but I'd be interested in the rest of the markings on these mis-marked chips, if you wouldn't mind. We still use those parts on an old CPU board of ours.
Thanks.
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.
Am I missing something? Are you saying a 82c87 was put into a product, tested, and only later started acting like a 82c86?
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