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ADS1232: ADS1232 Span change issue

Jackson Xu
Prodigy 40 points
Part Number: ADS1232


ADS1232 span change issue. when we power on/off ADS1232 multiple times, same analog input signal will get different digital output

  • 0
    TI__Mastermind 24195 points

    Hi Jackson,

    could you share some more details on your setup, schematic, and ADC configuration?
    How different in terms of codes are the conversion results after the different power cycles?

    Regards,

  • 0
    TI__Guru** 113765 points

    Hi Jackson,

    The issue you are seeing is most likely caused by an incomplete POR of the ADS1232 device.  Make sure that you hold the PDWN pin low for at least 10us after both the analog and digital supplies have reached nominal operating voltage.

    Pulsing the PDWN pin will reset the device except for the offset calibration register.  Once the PDWN pin is set high the first time wait until the ADS1232 has started the internal oscillator and started a conversion.  I suggest waiting for the first falling edge of the DOUT/DRDY which signals and end of conversion and verifies that the ADC has successfully started.  You do not have to wait this long, but I would suggest you delay at least 1ms.  Pulse the PDWN pin for at least 26us.  I recommend 100us or longer to ensure that any capacitance on the PDWN line is not an issue.

    After the PDWN pulse a new conversion will start.  Wait for the conversion to complete, then issue a self-offset calibration by sending at least 26 SCLKs to the ADS1232.

    Best regards,

    Bob B

  • 0
    Prodigy 40 points

    I changed the POR per suggestion, it seems solve the POR problem. we still keep testing during production stage.