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ADS1256: Differential Inputs and Single-Ended Inputs

xiaoqing liu
Prodigy 40 points
Part Number: ADS1256

I want to know ADS1256 can work in Differential Inputs with 1 -2 3-4 5-6  and  Single-Ended with 7  8. If it can work I think the AINCOM should  tied to a midpoint reference .Is that so?

  • 0
    TI__Mastermind 44571 points

    Hi Xiaoqing,

    You can see in the ADS1256's MUX register that you can select any analog input as AINP or AINN. Therefore, the configuration you proposed is certainly valid, you would just need to change the value of the MUX register each time you want to change channels.

    AINCOM could be tied to ground or to some other voltage, it really depends on the signals you are measuring and how you want to use the ADC's full-scale range. You should also consider that if the buffer is enabled then the input range is slightly limited and you should not be measuring ground-referenced signals with the buffer enabled.

    -Bryan

  • 0 in reply to Bryan Lizon86
    Prodigy 40 points

    Thank you for your reply,My Single-Ended signals  is 0-VREFP and VREFN tied to ground,So AINCOM could be tied to ground.But datasheet say The following。

  • +1 in reply to xiaoqing liu
    TI__Mastermind 44571 points

    Hi Xiaoqing,

    Yes, as I mentioned in my previous post, you can tie AINCOM to ground or you can tie AINCOM to some other voltage. The datasheet is just stating that AINCOM does not have to be tied to ground, as some designers might infer.

    If you are measuring between 0 and VREFP, then you would want to tie AINCOM to VREFP/2 to be able to use the ADC's full code range.

    -Bryan