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ADS125H02: ADS125H02 calibration guide

Eric Lo72350
Intellectual 915 points
Part Number: ADS125H02

Hi 

Do you have ADS125H02 calibration guide?


(1) for ADC calibration，DATASHEET Page41~44 , how to setting or calibration?



(2)for ADC digi filter，DATASHEET Page.33-38 how to setting or calibration?


Eric

  • 0
    TI__Mastermind 44680 points

    Hi Eric,

    The ADS125H02 datasheet is closest thing to a calibration guide that we have at the moment. If you look a few pages further, starting in section 9.4.5.4, there is an overview of the calibration procedure; however here are some additional details...

    Offset calibration should always be performed BEFORE gain calibration to remove the offset error from the measured gain error. Offset calibration simply requires providing a 0V input signal (usually by shorting the input to some common-mode voltage - it is very important to make sure the inputs are biased correctly, even when shorting them!) and then measuring the offset. NOTE: You can short the inputs internally inside the ADS125H02, but it is preferable if you (externally) short the inputs of the system to account for any offset errors external to the ADC. 

    You can either measure the offset directly and then manually update the OFCAL[2:0] registers, but it can be easier to provide the proper configuration (or external connection) and then issue the "OFSCAL" command to allow the ADC to perform the measurement and update the OFCAL[2:0] registers automatically.

     

    Gain calibration is similar but differs in that you need to apply a 100% full-scale (FS) signal (or a signal as close to FS as possible) instead of a 0-V short. You can issue the GANCAL command to allow the ADC to automatically calculate the gain error and update the FSCAL[2:0] register, but note that this operation expects a 100% FS input.

    If you applied a 95% FS signal, you may want to modify the ADC's gain calibration result, otherwise the ADC will output the FS code (7FFFFFh) when a 95% FS input signal is provided. See the following E2E thread for details about how to correct for this case: https://e2e.ti.com/support/data-converters/f/73/p/826632/3057713 

    There is no calibration for the digital filter; however, the digital filter you select will be used during calibration. You should try to configure the ADC (data rate, filter, gain, etc.) for calibration, the same way you intended to use it. For example, changing the PGA may result in a slightly different gain error, so calibrate the ADC using the gain setting you intend to use.

    I hope that helps!