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ADS1148-Q1: Reference mode Ext, Int，

Neal Zhu
Expert 2470 points
Part Number: ADS1148-Q1

Conversion Result = (VREX / 4) / VREF，What does this mean？and，How much accuracy can be achieved，at external voltage reference。

  • 0
    TI__Guru 52722 points

    Hi Neal,

    Your image didn't come through. Can you re-post the image?
    Are you referring to 9.3.12.2 External Voltage Reference Monitor in the datasheet?

  • 0 in reply to Alexander Smith
    Expert 2470 points

    Hi Alexander,

    NO,ti's  8.3.12.2 External Voltage Reference Monitor, Conversion Result = (VREX / 4) / VREF what dose this mean,and,when external voltage reference,How much accuracy can be achieved.

    Thanks.

  • 0 in reply to Neal Zhu
    TI__Guru 52722 points
    Hi Neal,

    Apologies, I was consulting the non Q-1 version of the datasheet.

    You have identified an error in the datasheet, it should be:

    Conversion Result = (VREX/4)*(2^15/VREF) as derived from:

    Code/2^16 = VIN / (2 x VREF)
    Code/2^16 = (VREX / 4) / (2 x VREF)
    Code = (VREX / 4 ) x (2^15 / VREF)

    It appears that the previous section is also incorrect, I appreciate you bringing this to our attention.

    I do not have a specific number available for accuracy as it depends on a variety of factors. As noted in section 8.3.12, the result is "coarse".