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INA111: Output Current Protection

Kaue Morcelles
Prodigy 30 points
Part Number: INA111

Hello,

I am working with an INA111 powered with a symmetrical source of +-5V, and the output needs to be single supply (5V). I added an Schottky diode (parallel to the output) to prevent this voltage to be negative. I want to know if I need to connect a current limiting resistor to protect the output or the INA111 will limit it and be ok with that. 

Thank you,

Kaue 

  • 0
    Guru 140200 points
    Hi Kaue,

    yes, I would insert a current limiting resistor of about 1k. Depends a bit on your circuit. The resistor would not only limit the output current of INA111 but the negative supply current as well. Another advantage of a reduced output current would be a reduced voltage drop across the Schottky diode. And the output would be isolated from the capacitive load of Schottky diode (junction capacitance).

    Kai
  • 0 in reply to kai klaas69
    TI__Genius 11135 points
    Kaue

    The INA111 minimum power supply voltage is +-6V. Even if you used a +-6V supply you would only be able to get a positive output swing to about +4V at best, assuming zero common mode input voltage.

    If you could provide a bit more information such as schematic, input (type of sensor, excitation voltage) and gain, then we should be able to suggest a solution.


    Regards
    Dennis
  • 0 in reply to Dennis Goeke
    TI__Genius 11135 points
    Kaue

    We haven't heard back from you so we assume you were able to resolve your issue. If not, post a reply below, or create a new thread if this one has timed-out.

    Thanks
    Dennis