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ADS8684: External Reference Range

Lukas Hartung29
Prodigy 20 points
Part Number: ADS8684

Hi

Do I understand the datasheet correctly that the external reference voltage has to be 4.096V +-50mV? Can it be smaller?

In my application i have to measure 0-2V and therefore would loose over 1bit (and i don't want to add an amplifier for each channel)

Thank you

Lukas

  • 0
    TI__Mastermind 35520 points

    Hello Lukas,

    Welcome to E2E community.

    To get specified performance shown on ADS8684 datasheet, the external reference voltage will have to be limited to 4.096V (4.046V to 4.146V range), also the minimum input range is 5.012V for unipolar signal.

    Since your signal range is only 0~2V, I would like to suggest you to select ADS8684A which has more input ranges(5 bipolar input ranges and 4 unipolar input ranges), you can configure ADS8684A to work with 0~2.56V range once after power up the ADC, there is no need to use any external amplifier to drive the ADC because ADS8684 has integrated PGA and ADC driver on every channel.

    Please let me know if you have more questions.

    Thanks.

    Best regards

    Dale

  • 0 in reply to Dale Li
    Prodigy 20 points

    Thank you very much Dale! I completely missed the "A" Version which is perfect for my application