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ADS1255: ADS1255

Jane Xu
Prodigy 10 points
Part Number: ADS1255

we use the 8MHz oscillator and add a clock buffer to drive 2 ADS1255. but there are always the noise on the ADC input. The noise is 4 times frequency of clkin. and noise happens when the clkin signals in high period. The noise is 2MHZ. 

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    TI__Mastermind 44680 points
    Hi there,

    Welcome to the TI E2E forums!

    I'm afraid I don't fully understand the problem other than you're seeing higher than expected noise.

    The data rate of the ADS1255 is much smaller than the CLKIN frequency, so are you seeing noise around the frequency where you would expect the CLKIN frequency to alias?

    What do you mean by "noise happens when the clkin signal is in high period"?

    What data rate are you configuring the ADS1255 for and how much noise are you seeing?

    Also, what is your input signal when measuring the noise? Are you shorting the inputs?


    I always recommend testing the noise with shorted inputs first, so that you can compare the noise performance to the datasheet. If the noise performance is close to what you see in the datasheet, then likely the signal your applying is noisy. If you're not able to get noise performance close to that of that datasheet with shorted inputs, you may have other problems, for example there could be an issue with the PCB layout.

    Best regards,
    Chris