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ADS1256: maximum sample rate

Amy Luo
Expert 6895 points
Part Number: ADS1256

Hi team，

I would like to know if ADS1256 can reach 30KSPS when fCLKIN= 7.68MHZ and using single channel continuous acquisition?

If it can reach 30KSPS, the output data （30K × 24bit per second ）of SPI interface are stable and up-to-date?

According to the datasheet table 15, when data rate = 30ksps, setting time = 5 DRDY periods, which implies that the maximum rate is less than 30ksps or not real-time data?

I want to fight out the meaning of table 15.

Best Regards,

Amy Luo

  • +1
    TI__Mastermind 46401 points

    Hi Amy,

    The information in Table 15 is related to multiplexing through channels. The ADC digital filter takes some time to settle when the device powers up and when the input mux is changed. As Table 15 says, this takes 5 DRDY periods when you are sampling at 30kSPS. This means the first settled conversion result is going to be available in ~ 30 kSPS / 5 = 6 kSPS.

    However, if you are continuously sampling on the same channel, then second and subsequent conversion results will be available after each subsequent DRDY period.

    Therefore, the first conversion result will be delayed by the time specified in Table 15, but all conversion results after the first result will be available at the selected data rate, which is 30kSPS in your case.

    Let me know if this is unclear

    -Bryan