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LMP90100 parameters

Peter Clerico
Intellectual 550 points

Hello,

I am trying to determine the input current and offset voltage when the input buffer is bypased.  The electrical specs in the datasheet don't appear to address these specifically.

Thanks in advance for any input/advice.

  • 0
    TI__Intellectual 1635 points

    Hi Peter,

    I think I received this same question of yours through Leonard Ellis as well.  Please give me a day to gather this fact for you, so I'll respond again tomorrow.

  • 0
    TI__Intellectual 1635 points

    Hi Peter,

    The buffer has minimal impact on offset voltage. Offset voltage is dependent of enabling or disabling offset cal. With continuous cal, offset < 10uV (see exact number in datasheet). Without cal, offset can be as high as 200uV.

     The input current with buffer OFF is dependent on input voltage, gain, ODR settings, and is given by the equation: I_in=Cs*Fmod*Vin  where

    Cs=4pF for Gainx1

    Cs=8pF for Gainx2

    Cs=16pF for Gainx4

    Cs=32pF for Gainx8

    Fmod=220KHz for SPS>13.5Hz output sample rate

    Fmod=13.7KHz for SPS<=13.5Hz output sample rate

    Vin = abs(Vin- 0.5*Va) V, where Vin is voltage on the input pin and 0.5*Va is the internal common mode voltage (half the analog supply voltage).