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ADS1292R: Abnormal input impedance test

Chu Allen
Intellectual 790 points
Part Number: ADS1292R
Other Parts Discussed in Thread: ADS1293

Tool/software:

Dear team,

We have a product that uses ADS1292R for data acquisition chip. During performance testing before submission, we discovered an issue.

According to "YY 9706.247-2021", we tested its input impedance and found that there was a problem with its input impedance.

When a bias voltage of ± 300mV is applied, the amplitude of the output waveform is significantly reduced as S1 is opened and closed.

But we did not encounter this issue when testing with ADS1293. The attachment contains the testing method and our test results. Please help to see what caused it.

  • 0
    TI__Guru 66186 points

    Hello,

    Thank you for your post.

    I would suggest checking the outputs of the PGA and ensure that signal is not swinging too close to the AVDD or AVSS supply rails. You may need to reduce the PGA gain or adjust the input common-mode voltage coming from the RLD.

    Regards,

    Ryan