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INA238: high sense voltage request

Mark Chen52
Expert 5695 points
Part Number: INA238

Hi Expert,

Customer is looking for high input voltage 48V at least on VIN+/- pin, but I only found INA238 has 40V voltage rating on VIN+/- pin. 

So could you help to check if we have other solution can support 48V on sense pin? if no, could you help to know how to achieve it with INA238?

Regards,

Mark

  • +1
    TI__Mastermind 26660 points

    Hey Mark,

    The INA238 can support an input common-mode voltage of 85-V maximum. The max differential input voltage rating is 40-V, but this rarely occurs as it could only happen if the shunt resistor is disconnected and one pin is pulled to ground and the other pin is pull to 40-V or if load becomes very high and Vshunt >40-V.

    Sincerely,

    Peter

  • 0 in reply to Peter Iliya
    TI__Expert 5695 points

    Copy that, thanks Peter.

    Regards,

    Mark

  • 0 in reply to Mark Chen52
    TI__Expert 5695 points

    Hi Peter,

    Could you help to double check the design if have any risk or not?

    the VSENSE_R and P48V_PSU_R will be 51V  of maximum voltage.

    regards,

    Mark

  • 0 in reply to Mark Chen52
    TI__Mastermind 26660 points

    Hey Mark,

    I cannot perform a complete analysis of this circuit with information provided; however, if the  input voltage won’t exceed 51-V, then is very low risk as it does not get close to the 85-V limit. 

    Be sure that can’t be transient input voltages exceeding 85V even for short microsecond periods of time.

    In terms of accuracy make sure that the shunt/sense voltage is less than the max input full scale range of the device per temperature and worst case scenario (e.g., tolerance and drift of the shunt resistor).

    Best,

    Peter