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Original question:

INA148: Differential input without supply

INA148: +/-10V at input without supply voltage

Olrik Maier
Expert 4830 points
Part Number: INA148

Hi Amps Team,

I have found the threat where 15V without Vsupply are OK, but what happen if there is a voltage of +/-10V at the input when the part is not powered.

Many Thanks

Best wishes,

Olrik

  • +1
    Guru 284990 points

    The absolute maximum ratings allow up to ±200 V, so the leakage currents will not do any damage.

  • +1
    TI__Guru 64290 points

    Olrik,

    Under unpowered conditions applying voltage to the inputs of INA148 will forward bias ESD protection diodes and result in the current flow limited by the internal input resistors of 1M - see below.  Thus, as long as the current magnitude is less than typical +/-10mA no damage may occur.  In the case of +/-10V input, the input current will be limited to just Iin=(10V-Vbe)/1M or ~9.5uA.  Therefore, nothing to worry about it.