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ADC TOTAL ERROR

Pablo Fernandez Comesana
Prodigy 20 points


Hello, I´m working with the F28035 Piccolo uC and I need the total error of the ADCs of that microcontroller, The datasheet give me four errors: INL, DNL, offset error and Overall gain error. The total error is: sqrt (INL^2+DNL^2+...)? Otherwise, How can I calculate the total error of the ADCs of the microcontroller?

Thank you for your answers.

Kind regards.

  • 0
    TI__Genius 16381 points

    Pablo-

    Unfortunately C2000 has not been in the habit of spec'ing total error, but as you have suggested one common practice is to take the square root of the squares of the various errors.  This does tend to be a pessimistic number since each datasheet spec is worst case performance across operating conditions and the parameters are not likely to be worst case at the same temperature, supply voltage, or ADC input voltage.

    Since INL is the accumulated DNL, you need not add DNL to your calculation.  Likewise channel to channel offset and gain will be comprehended by the offset and gain specs, so you should only need to use INL, offset, and gain.  Also Gain when spec'd as LSB is the gain error at the full scale voltage, so it may make more sense to convert all the errors to percentage.

    Regards, Joe

  • 0 in reply to Joe Prushing
    Prodigy 20 points

    Hello Joe,

    Thank you for your answer.

    Regards.

    Pablo