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INA212-Q1: how to protect MCU pin connected with OUT pin

Takao Yamamoto5
Expert 1690 points
Part Number: INA212-Q1
Other Parts Discussed in Thread: INA212

Dear all,

We concern the situation when IN- pin and OUT pin is shorted.

We connect IN- pin to 12V and OUT pin to 5V MCU.

So, if they are shorted, MCU I/O pin will be broken by 12V.

Could you teach us the countermeasures to protect MCU pin?

Best regards,

  • 0
    Guru 140200 points
    Hi Takao,

    this would destroy the INA212 as well, if its supply voltage is smaller than 12V! But why should there be a short circuit between these two pins?

    The usual method to protect the following ciruitry against overvoltage is to use a zener clamp, a diode clamp to the rails or a simple current limiting resistor. It depends on the mcu which method is best suited.

    But again, why should there be a short circuit?

    Kai
  • 0 in reply to kai klaas69
    TI__Mastermind 27390 points

    Hi Takao,

    If I interpret your concerns correctly, you worry that the voltage on input pins might somehow appear at the output. What I can say is that the paths between these two nodes are extremely high impedance. The likelihood for such scenario to happen is virtually zero. In case there is a catastrophic failure of the device, it is far likely for the output to rail to either end of the device supply than a short between output and input to occur.

    Regard, Guang

  • 0 in reply to kai klaas69
    Expert 1690 points
    Hi kai,

    In terms of 'pin FMEA', we must think the situation that the pin is shorted with neighboring pin.
    Therefore, we would like to know how to take measures if you know.

    Thank you for your advices.

    Best regards,
  • 0 in reply to Takao Yamamoto5
    Guru 140200 points
    Hi Takao,

    we coat pins which are critical with 1-K silicon rubber or we use a highly elastic 2-K PU potting compound. The coating is applied after the PCB was cleaned and tested.

    Kai