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Original question:

ADS1281: How to calibrate ads1281?

ADS1281: Built In Test

Nir Flysher
Expert 3287 points
Part Number: ADS1281
Other Parts Discussed in Thread: ADS1282, DAC1282

Hi Team,

My customer is working with the ADS1281 and wants to design a built-in-test into his system in order to make sure the ADC is properly configured and ready to be used.

The hardware is ready and it is not possible adding any external switch for an external test signal.

As a results we're looking for a way to do one of the following :

1. Is it possible to program the device to sample it's V_ref ?

2. Do we have any internal test signal we can generate (e.g. DC / sine wave / any other waveform) ?

3. Any other recommendation to test the device ?

Best regards,

Nir.

  • 0
    TI__Mastermind 44610 points
    Hi Nir,

    The ADS1281 does not have an internal MUX to allow for sampling of signals other than the analog input pins. Also, the maximum differential signal that can be measure is +Vref/2, so the reference voltage would have to be divided down before feeding it into the analog inputs.

    The recommend way to provide a test signal to this device would be to use the DAC1282 or some other very low THD source. Typically, most customers will use the ADS1282 + DAC1282 on their PCB, and dedicate one of the differential inputs of the ADS1282 to the DAC. Unfortunately, we do not have a stand-alone EVM for the DAC1282, so an external signal generator would probably be the easiest way to test their existing hardware.
  • 0 in reply to Christopher Hall
    TI__Expert 3287 points

    Hi Chris,

    Thanks for the prompt response.

    Unfortunately changing the hardware is not possible at this point.

    Is there any set of registers we can read back maybe to make sure the device is fully configured and ready to be used ?

    Regards,

    Nir

  • 0 in reply to Nir Flysher
    TI__Mastermind 44610 points

    Hi Nir,

    Yes, as long as you are not operating the ADS1281 in pin mode, then you can configure and read-back the device settings with the RREG and WREG commands.

    You can also use the /DRDY output signal as a kind of "heartbeat" to know if the ADS1281 is actively converting.