[sdiy] Dead TL072

n.pipenbrinck at hilbert-space.de n.pipenbrinck at hilbert-space.de
Mon Mar 20 12:59:59 CET 2017


Hi Tom,

> I checked everything over and the circuit it was in was not the cause.
> Instead it was a chip that I've abused for much too long and it finally
> gave up the ghost. I have a few TL072s in a piece of antistatic foam that
> I use for breadboarding, and some of them have been in this role for years
> - possibly 20 years - so they've really taken a beating one way or
> another.

I've never seen an opamp fail like this either, but be glad it died.

Most likely the prior beatings that the chip had to endure completely
altered it's characteristics like input offset voltages, slew-rate and
whatnot.

This saves you from taking measurements, designing a circuit, ordering
PCBs all based on a broken-but-still-working-chip. And then, when you
stick a fresh chip into your new circuit you'll find out that the altered
characteristics have become an essential part of what makes your circuit
work :-)

Been there, done that. I avoid re-using parts since then.

/Nils




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