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ADS1282: Gain matching of ADC

Eren Erdogan
Intellectual 280 points
Part Number: ADS1282


Hi all,

Firstly, I'm confused about gain matching parameter in ADS1282 datasheet. As i understood, gain matching is the difference between gain errors of two different input channels and  the difference is maximum 0.8%.

For example; AVDD=5V, AVSS=0V, VREFP=5V, VREFN=0V difference between gain errors of two input channels is 40mV. Am i right?

Therefore, secondly, do we need separately calibrate gain of two input channels?

Best Regards,

Eren

  • 0
    TI__Mastermind 44680 points

    Hi Eren,

    Great question!

    The gain matching specification is the matching between the various gain settings with respect to the PGA gain of 1 V/V. In other words, after you've corrected for the systematic -1% gain error (i.e. performed a calibration at one particular PGA gain setting), how much residual gain error will be left if you switch to a different PGA gain setting. The gain matching between channels should be very well matched since both channels share the same PGA and ADC.

    • If you plan to use multiple gain settings, you could calibrate at one of those settings and live with the result gain matching error for the other gain settings.
    • Otherwise, you could perform multiple calibrations at each of those gain settings to remove the gain matching error; however, this is not always practical.

    Let us know if you have any additional questions!

    Best regards,
    Chris