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INA180-Q1: suppress negative voltages at input when switching off inductive loads

Thomas Hertzberg
Prodigy 10 points
Part Number: INA180-Q1
Other Parts Discussed in Thread: INA180, INA195A-Q1

Hello community,

We want to measure current with a shunt resistor and INA180. Current might get to inductive loads so when switching off, we expect huge negative voltages (kV). We already placed TVS diode to limit to -24V.

Input voltage (common mode) must not be less than -0.3V. With additional (Schottky) diodes we could not limit the voltage due to high free wheeling current and therefore forward voltage goes above 0.3V.

We also had a look into INA195A-Q1 which can handle -16V. That one also needs additional protection (-24V vs -16V) and has high cost compared to INA180.

Is there a simpler/cheaper solution available?

Thank you very much for your support!

  • 0
    TI__Mastermind 27390 points

    Hi Thomas,

    We have LMP860x family of devices that can withstand -22V common mode. Would you be able to compromise on the TVS clamping voltage and consider one of them?

    Even though INA180 offers best price over performance, the limited negative input range of INA180 makes it a challenge to protect agaist large negative inputs.

    Regards, Guang