I have an LM7332 that is creating a gate voltage to drive a MOSFET. The circuit failed in the field and I'm trying to debug. One thing I've noticed is that the supply voltage to the MOSFET was sometimes low, which meant that the LM7332 had been outputting a voltage right at its V+.

Does this do any harm to the OpAmp? A simulation showed that I(V+) was 1.2mA, I(Vout) 0.8mA and I(V-) 0.4mA so all seems kind of benign as per the spec sheets. Except VOut=V+ ... Could this have been the cause of the LM7332 to die?

Thanks, T.

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    \$\begingroup\$ In case it might be relevant -- in which way did the circuit/op amp fail? Were you able to take it back for analysis and testing? The LM7332 is rail-to-rail so it shouldn't fail in this manner from being driven to the rail alone, but other voltages/currents being out of spec may cause it to malfunction or be damaged. \$\endgroup\$ – nanofarad Apr 13 at 15:06
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    \$\begingroup\$ Very doubtful. More likely something related to the MOSFET circuit walloped the output. \$\endgroup\$ – Spehro Pefhany Apr 13 at 15:08
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    \$\begingroup\$ Show your op-amp MOSFET interface schematically and make sure all the nominal value of the power rails are indicated. \$\endgroup\$ – Andy aka Apr 13 at 15:47
  • \$\begingroup\$ Circuit is getting shipped back to us now. I'll upload a schematic shortly. \$\endgroup\$ – Tunneller Apr 13 at 19:44

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