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is there any loading effect on lmp90080 adc ic inputs?

vijay kumar2
Intellectual 270 points
Other Parts Discussed in Thread: LMP90080

Hello,

           I am using lmp90080 for reading voltage in the range of micro volts, I have one calibration meter which will produce micro volts.

          The problem here i got is when I am switching on the calibration meter without connecting as adc input it is giving constant micro volts, But when I connected as adc input it is varying 10 to 20 micro volts. 

            Is there any loading effect on adc input, Kindly show me a solution for this problem.

Thanks in advance

vijay kumar

  • 0
    TI__Genius 16890 points

    Hi,

    The input impedance of the LMP90080 is 15.4Mohm.  What is that in comparison with the impedance of the meter.

    Also check to make sure that it is not in scanmode3 with the burnout currents enabled.  That would cause a variation.

    You can also try setting it up with the FGA bypassed and the buffer enabled.

    Mike