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I've designed a circuit but realized now - when the 200+ boards finally arrived - that I've made a mistake.

Long story short: I made the prototype on a breadboard, using OPA2132 (because that's what I had at home) coupled as a comparator (fixed ref at in-, signal at in+). The breadboard version somehow worked like a charm, but when sitting on the PCB the output is never brought down to GND when in- (6.5V) > in+ (1.8V). Instead, the output is around 1V, and that screws everything up.

Being a hobbyist, I cannot afford to buy new boards, so the only solution here is to find pin-compatible comparator (SO8) that does not cost a fortune, that I can replace. OPA2132 is not open-collector. Vcc for my circuit will never be over 13V, and it's single fed (no negative voltages).

How can I find a replacement IC without browsing through zillions of datasheets?

OPA2132 datasheet: http://www.ti.com/lit/pdf/SBOS054

bos
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    you're not giving us the whole picture. any opamp an comparator will most definitely emit negative when in- >> in+ (which is very clearly the case here). So, there's something else wrong here, and replacing the comparator won't help. Maybe you'd first want to ask a different question: "I have this {schematic}, and with in- = 6.5V, in+ = 1.8V, I don't see low-level output. Why?" – Marcus Müller May 19 '17 at 08:39
  • @MarcusMüller: You may have a point here. The PCB is an exact replica of the circuit on the breadboard, and that circuit works as expected. Perhaps I have soldered a short somewhere. I will check this first. Thanks. – bos May 19 '17 at 08:43
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    check the voltages at every point with a multimeter, and also make sure the OPA isn't simply broken. – Marcus Müller May 19 '17 at 08:45
  • The OPA2132 is not a rail-to-rail op amp. I wouldn't expect it to go down to ground, if ground is one of your supply rails to the amplifier. – Hearth May 19 '17 at 15:10
  • In the future it'd be better to [avoid using an op amp as a comparator](https://electronics.stackexchange.com/a/194324/51760). – Null May 19 '17 at 16:27
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    What load is the op amp driving? Show us the circuit and PCB layout. – Bruce Abbott May 21 '17 at 18:05

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