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ADS1261: ADS1261

Nathan Mayes
Prodigy 10 points
Part Number: ADS1261
Other Parts Discussed in Thread: ADS124S08, ADS127L11

Tool/software:

Hi TI,

The design I am working on needs 6 differential inputs and the specification of the ADS1261 ADC. I see that the there are a few NC pins on pins 19 - 22 and was wondering if there is an ADC that has the same PGA / core as the ADS1261 with six differential inputs?

Thanks,

-Nate

  • 0
    TI__Guru 52496 points

    Hi Nathan Mayes,

    The ADS124S08 has 13 input pins, so 6 differential pairs are possible. The ADS124S08 is the closest released device that is similar to the ADS1261

    What is your application, what are you trying to measure with the ADC? Perhaps there is a better alternative we can offer

    -Bryan

  • 0 in reply to Bryan Lizon86
    Prodigy 10 points

    Hi Bryan,

    I am setting up a long term data logging device to measure drift on a sensor that has a small output range (max 160ish mV). The test will run for months and the accuracy of the ADC is critical over sampling rate or the number of inputs the device may have (I was looking at using an external mux).

    Regards,

    -Nate

  • +1 in reply to Nathan Mayes
    TI__Guru 52496 points

    Hi Nathan Mayes,

    The ADS124S08 is a good choice then if you want to measure 6 differential inputs using a single device. Of course as you said you can always use an external mux and then choose a single-channel ADC.

    I assume you will use an external voltage reference for best performance (and lowest drift, noise, etc.)? I would also encourage using the input chop feature in the ADS124S08, which swaps the polarity of successive measurements to cancel out the offset (and therefore offset drift). This increase the overall latency per channel, but maybe this is acceptable in your system since it will reduce the long-term error

    If you want a single-channel device, check out the ADS127L11. This is a low noise, high-speed, high accuracy delta-sigma ADC. You would need to add an external gain stage + mux, but it sounds like your key careabouts are precision and accuracy, not necessarily size or cost. If you only need a single gain for the sensor, it might be easier to use a low noise INA.

    Let me know if you have any additional questions

    -Bryan