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ADS131E08: Achieving 15360 samples per second @ 24Bit with it!

Ali Asadzadeh
Intellectual 290 points
Part Number: ADS131E08

Hi,

I was  finally able  to capture data from this ADC @16K SPS @ 24Bit, correctly in continuous conversion mode, however I want to be able to sample @ 15360 SPS.

The problem with this is either I'm stick to use  continuous conversion mode (which is a fixed sample rate) or discontinuous  conversion mode, with the second method I should be able to achieve custom sample rates, but the problem with that mode is that I takes a lot of clock cycles to be valid for each conversion, so with this method I can not achieve the desired sample rate. so the question in here is how can I achieve this sample rate? is it possible with this part or is it a bad design that can only accept fixed sample rates!

  • 0
    TI__Guru* 97955 points

    Ali,


    The ADS131E08 is only able to run at set data rates. The oversampling can only be done at specific ratios. You can see the data rates based on the DR bits in the CONFIG1 register with the expected noise performance in Tables 1 and 2 of the datasheet.

    However, you should be able to change the data rate small amounts with a change to the master clock. Assuming that you're running with a master clock of 2.048MHz, you should be able to lower your data rate a little from 16000SPS to 15360SPS. For that, you would need a master clock frequency of 1.96608MHz. This comes from:

    2.048MHz * (15360/16000) = 1.96608MHz

    This is not the most common clock frequency, but they are available. I would note that the master clock for the ADS131E08 is limited to a period of 588ns to 444ns. That would be about 1.7MHz to 2.25MHz, this is listed in the Timing Requirements on page 19 of the datasheet.


    Joseph Wu