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Whether ADS1263 will achieve low performance using a different clock other than 7.3728MHz?

Other Parts Discussed in Thread: ADS1263

Hi, there

ADS1263 is planned to be used as data converter for our project. And I want to get a different data rate from datasheet. e.g. 1000 samples per second. So I guess a different clock other than 7.3728MHz should be used. But I am not sure whether performance loss will accur? Any advice will be appreciated.

Best Regards

Yang

  • Hi Yang,

    You can certainly use a different clocking frequency to achieve 1000 SPS. For example, configure the ADS1263 for the "1200 SPS" data rate with a 6.144MHz clock to achieve 1000 SPS ( = 6.144 MHz / 7.3728 MHz * 1200).

    Applying a clock within the 1 MHz to 8 MHz specified range should not have a significant impact on performance. However, the DVDD current will scale with the clock frequency, as shown below.

    Power Consumption vs. Clock Frequency

     

    fCLK

    AVDD Current

    DVDD Current

    (MHz)

    (mA)

    (uA)

    10

    4.27

    1290

    8

    4.20

    1060

    6

    4.13

    825

    4

    4.07

    591

    2

    4.00

    357

    Other than achieving a specific data rate, which performance specifications are important in your application?

    Best Regards,
    Chris

  • Hi, Chris

    Thanks for your quick and accurate reply. Noise performance is also important other than specific data rate.

    Best Regards
    Yang
  • Hi Yang,

    Unfortunately, I don't have any noise performance data for clock rates other than 7.3728 MHz.

    For relatively small changes in the clock frequency, you ought to see similar noise performance. Changing the clock frequency modifies the modulator's noise shaping characteristic, as well as the SINC filter response. For the most part, both of these will scale linearly with the clock frequency and result in about the same noise performance. I suspect the noise performance would begin to change as the clock frequency approached or exceeded the specified clock frequency limits. Therefore, using a 6.144 MHz clock instead of a 7.3728 MHz clock should not have much of an effect on the noise performance.

    Best Regards,
    Chris