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ADS8920B: Vcm range

Oba
Genius 17295 points
Part Number: ADS8920B

Hello,

I have a question for ADS8920B.
Its Vcm range analog input is specified as Vre/2 +- 0.1V. 
What kind of problem could occur if analog input Vcm is out of this range?

Regards,
Oba

  • 0
    TI__Mastermind 46200 points

    Hello Oba-san,

    The linearity will degrade if operated outside of the recommended common mode range.  The THD can degrade by more than 30dB as well when looking at AC signals.

    There will be no damage to the device, and it will still function and provide good SNR.  However, in the extreme case where one input is held at DC level of Vref/2, and the other varies from 0V to Vref, the THD will look more like a 12b converter than a 16b converter.

    Regards,
    Keith Nicholas
    Texas Instruments
    Precision ADC Applications