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ADS1248: Accuracy of system monitor measurements

Part Number: ADS1248

I would like to use the unused REF1P / REF1N inputs to make an additional measurement using the system monitor function.  The data sheet specifies that these are coarse measurements and that the resulting conversion is approximately 1/4 of the actual voltage.  Is there any further information on the accuracy of this measurement?

Thank you,

Nick Wright

  • Nick,


    The system monitors measurements are made up from voltage dividers internal to the device. As a result, the measurement is reliant of resistor match for accuracy.

    I generally won't rely on these measurements for anything better than 10% accuracy. I have looked a some of data just to see how accurate the measurements are.

    If I have to ball park the accuracy, I'd say that the AVDD accuracy is probably is about 5% and typically measures low. The DVDD accuracy is probably about 10% and typically measures high. The VREF accuracy is about 1-2% and measures a little low. This is from some older test runs but I don't think this would change much because the accuracy comes from resistor match.

    Again, we don't guarantee this specification. It's only for information. We've used it for burnout detection, measuring aspects of the circuit when we suspect the sensor has failed.


    Joseph Wu
  • Great, thank you for the fast response.