Just inadvertently reverse socketed a 4001 quad nor on a prototype. It got stinking hot, after I turned the power off I decided to just swap it round and try for luck. It works OK, just wondering how lucky this event was. Or is CMOS really reasonably (unofficially) reverse-polarity tolerant?
The supply rail is fairly stiff at 12V, it would have held up with at least an amp.
I've seen reversed 8748s (windowed microprocessor) with the internal power links glowing brightly. Put them in right way around and they work ;)
Reason is the substrate diode.
Grant.
It happened once to me with a guitar effect pcb containing no less than 5 or 6 opamps. All sockets soldered backwards so that the inspection before powering it up went ok. I kept that board powered a good half minute before realizing what went wrong, but it worked like a charm once the opamps were put back in the correct orientation.
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You are lucky. I once did this by mistake with a couple of 2716 ROMS. They didnt survive, and it was a huge hassle to source replacements from the USA
(this was circa 1985, and there was no internet)
In your case reverse protection diodes on the chip probably saved it, and you turned it off before they got too hot and do physical damage to the IC.
I remember a similar incident where a 6810 RAM had the negative pin folded up under it when inserted in the socket. This worked fine, even with no earth. It was discovered by accident some unknown time later (would be months/ years).
I think this is another case of the protection diodes on the pins saving the day by "making" a substitute path to negative. Obviously the chip could cop the voltage drop involved.
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