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ADS114S08B: Measuring 6 differential inputs at 2kHz

fabi
Prodigy 90 points
Part Number: ADS114S08B
Other Parts Discussed in Thread: ADS1261, ADS131E06

Hello!

I'm designing a device that measures current generated from electrochemical reactions. I need to measure 6 electrodes every 0.5ms (2kHz).

I read the datasheet but I'm not sure if with this ADC I'm gonna be able to take this measurements. Is there a way to calculate this? All the other specs are perfect for what I need.

Thank you!

  • 0
    TI__Guru** 112795 points

    Hi Fabi,

    The ADS114S08B has a mux with the maximum data rate of 4ksps.  There is also some additional overhead when using the low-latency digital filter.  So if you need to measure 6 electrodes, with a maximum data rate of 4ksps, 4ksps/6 is 667Hz (1.5ms period) total throughput discounting the latency.  So no, you cannot convert all 6 electrodes in 0.5ms.

    So you will require a faster ADC when using an internal mux.  You could take a look at the ADS1261 which is a faster ADC that uses a mux similar to the ADS114S08B or you could check out the ADS131E06 that has six simultaneous converters.

    Best regards,

    Bob B

  • 0 in reply to Bob Benjamin
    Prodigy 90 points

    Hi Bob,

    Thank you for your quick answer! I was looking at the ADC's you recommended. I have never worked with a simultaneous converter, is it easy to work with? Or given the amount of data generated you'd have to have certaing considerations when choosing which microcontroller to use?

    Thank you!

  • 0 in reply to fabi
    TI__Guru** 112795 points

    Hi Fabi,

    As to using a simultaneous converter and ease of use is difficult for me to say as I know nothing of your experience.  Generally the package is substantially larger so that could also be a possible issue compared to a device that uses a mux.  As to processing power, this would greatly depend on data rate (speed) in which you intend to make the conversions.  You need to read out the data completely before the next conversion period ends.  This may require operating with a fast SCLK frequency.  With a device such as the ADS131E06 you would trigger an interrupt at the end of the conversion to read all of the channel data at once.  Your firmware would need to separate the retrieved data into the various channels.  Check out the datasheet for detailed information.

    Best regards,

    Bob B