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PGA970: DAC accuracy estimation

[FAE] Andrew Wang
Genius 10685 points
Part Number: PGA970

Hi team,

Customer is asking if they want to manage DAC output swing full range to be 5V.

With calibration and without calibration, what are the best accuracy that PGA970 can achieve separately?

I cannot understand how to read the DAC spec, they look different from a regular DAC, please educate me if possible, thanks!

Andrew

  • 0
    TI__Mastermind 31655 points
    Hi Andrew,

    I would not recommend using the PGA970 without calibration to compensate for the sensor. I can't speak to the accuracy in a situation like that. Even when calibrated the accuracy will depend on the board, the sensor, and the calibration.

    As for the DAC spec, are you looking for information on the output DAC or the waveform generator DAC? The output DAC specification is at section 6.18 and 6.19 on the datasheet, and if you have some specific questions I'd be happy to answer them for you.

    Regards,
  • 0 in reply to Scott Cummins
    TI__Genius 10685 points
    Hi Scott,
    Thanks. The normal DAC spec we usually use RSS to estimate accuracy. If calibration is must then I would say in most cases, OFFSET DRIFT, GAIN DRIFT, INL and VREF errors are major ones in my calculation. But I cannot understand how to read PGA970 spec to find those terms maybe the DAC in PGA970 is not as straightforward as I thought could you plz give me an example how do we estimate the accuracy for calibration case? Say Ta change up to 50C, max +/-25C change. Thanks.

    Andrew
  • 0 in reply to [FAE] Andrew Wang
    TI__Genius 10685 points
    Hi Scott,

    Any update? Customer is waiting. Thanks.

    Andrew
  • 0 in reply to [FAE] Andrew Wang
    TI__Mastermind 31655 points
    Hi Andrew,

    Unfortunately I just do not have the data for those specific parameters for the DAC in the PGA970. If you want to look at the total internal signal chain error, you can find the offset, nonlinearity, and drift data for the ADC, the nonlinearity and drift data for the digital demodulators, and the linearity and drift data for the DAC gain stage in the datasheet, but that is all that is available.

    Regards,