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[FAQ] INA199: Dealing with device protection when you can't exceed -0.3V

Part Number: INA199

How do I protect against reverse current when I can only allow my signal to be 0.3V below ground?

  • We receive this question repeatedly in our forums. There is always a challenge when customers have the potential to apply more negative voltage than the part can handle because the available options aren’t great in dealing with this and are certainly not cheap.

    We have put together the following suggestions to our customers:

    1. Use a single diode in the power path, see this thread.
    2. Use PMOS FET in the power path, see this thread.
    3. Use nMOSFET in the ground path, see this TI App note.
    4. Use two normal rectifying shunt diodes off IN+ and IN- inputs, see this thread.
    5. Use Zener and Rectifying diodes, see this thread.
    6. Implement a comparator that will turn a MOSFET off if reverse polarity detected, see this thread.
    7. Use performance/smart diode ICs such as the LM74700-Q1LM74610-Q1, or the SM74611.
    8. Use low-noise bias generators such as the LM7705.



    TI makes no warranties and assumes no liability for applications assistance or customer product design. You are fully responsible for all design decisions and engineering with regard to your products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning your designs.