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Original question:

INA901-SP: Absolute Maximum Input Current Into Pins

INA901-SP: 5mA maximum input current on sense pin

Wes Clow
Prodigy 40 points
Part Number: INA901-SP

If the maximum input on sense pin is 5mA do I need to add external resistors in series with the internal 5k ohm resistors to limit the input current to the sense pins to below 5mA? If I do add external resistors I will try to 

  • +1
    TI__Expert 5790 points

    Hello,

    The 5mA input current limit is a bit of a misnomer in this circumstance. The voltage ratings of the part are more relevant for your use case because they describe the external stresses the part is designed for. The 5mA limit is more frequently used to describe the limits if you exceed to voltage rating, e.g. "if you operate the input pins at 70V the device will remain undamaged if you limit the current to 5mA" This shouldn't be an issue for regular operating conditions since the input bias current for the input pins is limited to ±8µA.

    The device is shown in figure 10 sourcing up to 32mA of current when short-circuited, so the device can certainly take more than 5mA on the power supply pin when it is operated in normal voltage ranges (2.7-16V) and the 5mA limit is probably meant to apply to voltages outside of this range.

    So in summary, if you limit the voltage on the pins to the rated conditions you don't need to worry about the 5mA limit because the device is designed for these voltages and will never draw more current than it can handle.

    Let me know if you need any additional clarification on this issue,

    Levi DeVries