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INA240: ESD Protection circuit for INA240

Yuanchen Zhu
Intellectual 425 points
Part Number: INA240

Dear TI Expert,

  In our case, we do need extra ESD protection circuit for INA240. Our INA240 configuration is based on ground referenced output topology. And we are aware that  HBM VESD is 2000V as stated in INA240 datasheet. If we would like to greatly enhanced ESD protection using external circuit, what type of protection topology and component would you recommend so that  current sensing application would not be affected either?

  And the ESD surge in our case comes from GND. INA was damaged when a minus voltage shock was applied on GND indirectly.

Regards,

Yuanchen

  • +1
    TI__Mastermind 34370 points

    Hi Yuanchen,

    Depending on the required input voltage range under normal working conditions, the external ESD protection can be as simple as a single TVS diode that clamps the input voltage to slightly below ground. This should be sufficient to fend off the negative ESD discharge you’re concerned about.

    Regards, Guang

  • 0 in reply to Guang Zhou
    Intellectual 425 points

    Hello, Guang

      Yes, I understand and agree with what you are saying, but I am still concerned about the accuracy of INA240's measurement at the same time. What is the recommended capacitance and leakage current of tvs diodes placed each for differential inputs would you say. so that the circuit can still tolerate to maintain a good accuracy. In our case, we are measuring a voltage across a 2 mili ohm sampling resistor in series with a power rail of 24V, and we are taking a measurement at a speed of every 5 sec.  If you have more advice to select tvs diodes or any more precaution in mind, e.g. noise consideration. please do tell us. Thanks again.

    Regards,

    Yuanchen

  • 0 in reply to Yuanchen Zhu
    TI__Mastermind 34370 points

    Hi Yuanchen,

    Under the specific use condition, INA240’s input bias current is around 100uA for each input pin. TVS diode’s leakage is typically far below this level.

    I don’t think there is going to be accuracy impact due to either capacitance or leakage current associated with the diodes.

    Regards, Guang