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Noise-free bits in ADS1298

Al Luis
Prodigy 225 points
Other Parts Discussed in Thread: ADS1298, ADS1299

Hello, I would like to know the number of noise-free bits and de dynamic range in the ADS1298 for each PGA Gain value.

From table 1 and table 2 in the datasheet of  ADS1299  it appears what I would like to know, but for the ADS1298 there is not any table like these and It would be really useful.

Could you help me please?

Thank you very much

  • 0
    TI__Mastermind 38745 points
    Hey Al,

    Unfortunately such a table does not exist at this point in time, but it is relatively easy to calculate those numbers from Tables 2 to 5 in the ADS1298 datasheet.

    For dynamic range, you simply divide the input referred full-scale range by the input referred noise. The input referred full-scale range will just be 2*Vref/PGA and the pk-pk input referred noise is given in the table. To obtain the value in decibels, just multiply 20 by the base ten logarithm of the ratio you calculated.

    To obtain the effective number of bits, you can simply convert each pk-pk input referred noise voltage to its output digital code and find how many bits are left untouched by the noise.

    Regards,
    Brian Pisani
  • 0 in reply to Brian Pisani
    Prodigy 225 points

    Thank you very much Brian ! It has been really useful !