There are indeed some strange 'counterfeits' around. Maybe they were a deliberate attempt to confuse reverse engineering of some product, but never used? or it could have been a simple mistake.
I have a few thousand MPSA92 which have been remarked from MPSA42, with the 4 and 9 superimposed. They work perfectly as PNP HV transistors so it's possible somebody just forgot to change the engraver text and the mistake wasn't noticed until they had a large pile of mismarked PNP MPSA42s. Tony. On Fri, 25 Jan 2019 22:38:43 +0000, you wrote: >Hi Bill, > >Indeed, it seems bonkers. I assume it's because someone has a huge stash >of open collector output 74 series shift registers, and either thinks >they're the same, or that most people won't notice the difference. > >I bought two batches of 500 of them, from two different chinese suppliers, >and they are all exactly the same, having the same laser engraved batch >number even. To be fair, the prices were suspiciously good, but I wasn't >banking on fake shift register ICs.... > >They are badged as TI SN74HC595N, and batch GM1807FSF. > >I have some 'normal' SN74HC595N, and swapping these out for the real ones >generates the expected behaviour ( and yes, inv G is indeed pulled low). > >With the 'fake' ones, they will appear to work OK with a pull up resistor >present (as you'd expect with an open collector output), but are unable to >source any current. > >I thought it was just me, but then I googled GM1807FSF and found someone >else (in German) having the same problem! > >https://www.mikrocontroller.net/topic/463936 > >David > >On Fri, 25 Jan 2019 at 22:24, Bill van Dijk <[email protected]> wrote: > >> That is really weird. Please understand I am not questioning what you are >> saying, but perhaps there is another explanation. The 74LS596 (I have never >> seen an HC version) is indeed an open collector chip similar to the >> 74HC595, which is a tri-state device. On the 74HC595 the inv G (pin 13) >> should be held low for normal operation. If it goes high for any reason, >> the output will float in tri-state mode, similar to what an open collector >> would look like. As you say, I can’t for the life of me not figure why >> anyone would bother to rebadge those chips especially since there does not >> seem to be an economic one (which is usually the motivation). >> >> >> >> Bill >> >> >> >> *From:* [email protected] [mailto:[email protected]] *On >> Behalf Of *David Pye >> *Sent:* Friday, January 25, 2019 4:12 PM >> *To:* [email protected] >> *Subject:* Re: [neonixie-l] Re: Counterfeit RTC modules >> >> >> >> It seems even things barely worth faking are being faked also. >> >> >> >> I have a bag of 500 74HC595 shift registers, that are actually rebadged >> 74HC596s (as in, open collector, SINK, not SOURCE-capable). >> >> >> >> Which are useless for my application :-( >> >> >> >> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "neonixie-l" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> To view this discussion on the web, visit >> https://groups.google.com/d/msgid/neonixie-l/008501d4b4fc%24bb636a80%24322a3f80%24%40gmail.com >> <https://groups.google.com/d/msgid/neonixie-l/008501d4b4fc%24bb636a80%24322a3f80%24%40gmail.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/dt6n4epl4q4pc6or71ghtcc0tgps04sf0e%404ax.com. For more options, visit https://groups.google.com/d/optout.
