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ADS1274: About PWDN[8:5] connection issue

Jenny Lu69
Expert 1810 points
Part Number: ADS1274

Hi Sir/ Madam,

I have some doubts about ADS1274. What datasheet said is PWDN[8:5] must be connected to ground. If I make the 4 pins float, what will be happened? That is to say,which performance will PWDN[8:5]  influence?

And as the time goes, my design in ADS1274(PWDN[8:5]floating) has the problem of a certain channel had a high noise than before, there is possibility with PWDN[8:5] floating? It confused me, could you figure it if possible?

Thank you.

Best Regards

  • 0
    TI__Guru 66346 points

    Hi Jenny,

    Thanks for your question.

    It's difficult to say with certainty what the effect will be. Generally, we recommend tying unused pins to either the positive or negative supply in order to minimize any leakage current. You might also see an increase in noise performance if they are left floating, but identifying the source of increased noise can be a difficult in ADC systems.

    You could try to short the PWDN[8:5] pins to ground with a wire and compare the results to see if this has a significant impact.

    How much noise are you seeing and what are the measurement conditions (i.e. input configuration, CLK, MODE, and CLKDIV settings, etc.)? Do you have results from an input-short test? By shorting the channel inputs together, you can analyze the noise performance for each channel with a histogram analysis.

    Best Regards,