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TPS7A88: Manufacture Testing Circuit Requires External Supply To Override Power Device

Dave Bailey1
Prodigy 10 points
Part Number: TPS7A88

We need to test circuit boards with the TPS7A88 on board supplying +3.3V to the circuit.  At the end of the test, we need to turn off power through the TPS7A88 and power the +3.3V bus using an external power supply.  Our question is, is the output of the TPS7A88 protected from external power being applied to its output?  No other power will be applied to the boards under test.

By the way, the two outputs are tied together in this circuit.

Thank you,

Dave

  • 0
    TI__Mastermind 29350 points

    Hi Dave,

    The datasheet absolute maximum lists the output pin as Vin+0.3V.
    If you turn off power to the LDO and 0V is on the input, then you can only go as high as 0.3V on the output.
    The internal pass element is an N-channel MOSFET, so at a minimum a higher reverse bias on the output would flow through the internal body diode.

    Based on this, I believe the linear regulator will exceed the datasheet limits and possibly be damaged if you reverse bias the output greater than the datasheet spec.

    Thanks,

    - Stephen