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INA240: Current required to drive reference pins?

Alpha H
Genius 10855 points
Part Number: INA240

Hi team, 

I was wondering how much current the INA240 reference pins are sinking during normal operation.

Also, what are the values of the resistors on REF1 and REF2?

Thanks,

Arthur

  • 0
    TI__Mastermind 34220 points

    Hi Arthur,

     The FEF pins have the following structure. R1 is 375KOhm.

     The REF pins can either source or sink current depending on how they are configured.

    If “Split supply” configuration is used, such that REF2=5V and REF1=0V, then REF2 is sinking current and REF1 is sourcing. The magnitudes of these two currents are equal, approximately 50uA each, or 5V/100K.

    If REF pins are tied together and driven with an external voltage source, Vext, then the two currents are identical. The direction of current flow depends on the magnitude of Vext. If it is less than 2.5V, then both pins source currents; otherwise both sink currents. The magnitude of the current is ABS(Vext -2.5) uA each. Here 2.5V is half supply assuming 5V is used to power the device. If 3.3V supply is used instead, then substitute with 1.65V in above calculations.

    Regard, Guang