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ADS7142-Q1: two channels affect each other

Hui Cao22
Expert 1270 points

Part Number: ADS7142-Q1

What could be the reason that the input collected values of the two channels of the ADS7142QDQCRQ1 chip affect each other during use? The power supply is normal. How to troubleshoot?

we use two-channel single-ended module.

SCH.jpg

  • 0
    TI__Mastermind 21330 points

    Hello,

    Sorry for the delay in response cause by the Thanksgiving holiday break in the United States.

    Usually, an error caused by switching between ADC channels signifies a settling error. The 2kΩ input resistor seems quite large, so it could be too big to allow the input to settle fully within the acquisition time.

    To confirm this suspicion, can you add a delay between the two channels' ADC conversions? Does a longer delay between conversions improve the error? Does a shorter delay make it worse?

    Regards,
    Joel

  • 0 in reply to Joel Meraz
    Expert 1270 points

    thanks for reply, Even when the delay was increased from 15us to 15ms, there was still interference. The input resistor of 2k is not connected. The direct input is the source. Please give some suggestions

  • 0 in reply to Hui Cao22
    TI__Mastermind 21330 points

    Hello,

    Can you share what is the expected value for AIN0 and AIN1, and what are the observed values? Does the delay make it better at all, or is exactly the same?

    How is the input voltage being supplied to the ADC?

    Regards,

    Joel