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about LMC7101AIM5 input

Vera Mao
Expert 5065 points

hi dear supporting team,

customer is using LMC7101AIM5 as their feedback amp in one power module,  now they found the input for PIN4 is -0.7V, which is lower than -0.3V as d/s states, so this would affect long term reliability, right? btw,  do we have ESD clamp diode at the input/output pin?  tks!

  • 0
    TI__Guru 64856 points

    Hello Vera,

    Yes. There are ESD protection diodes on every pin to both V+ and V-. They are seeing -0.7V on the pin because it is being clamped by the ESD diode to V-.

    If the current into the pin is limited to 1mA or less, there should not be any damage. This can be accomplished by adding a series resistor to the input to limit the current. About 1k per volt of expected over-voltage. So if the possible over-voltage is -12V, then a 12k series resistor should be used. Feedback or divider resistors can be counted as part of the series resistance.

    If this condition is expected to occur regularly, an external Schottky diode is recommended as the internal ESD diodes are not designed for continuous operation.

    Regards,