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ADS7054: Common-mode question

John Larkin
Prodigy 130 points
Part Number: ADS7054

Tool/software:

The ADC is described as fully differential, but the common-mode range is tightly specified near Vref/2.

Will it report, say, 1 volt input if AINP is +1.7 and AINM is +0.7? In other words, does it digitize the difference between the inputs even if the common-mode is not Vref/2?

What happens in the case above?

I have a 3.3 volt reference and a differential signal, both inputs always between 0 and Vref, common-mode typically 1.2v, but don't want to add another amplifier.

Thanks

  • 0
    TI__Genius 15150 points

    Hi John,

    You might still get an accurate value for a single sample, but it will be degraded in terms of noise and linearity especially over multiple samples of a dynamic input signal. In short, you will be outside the datasheet specs. I may be able to show you with our EVM GUI if this is something you're interested in.

    Regards,
    Joel