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ADS1281: About supply of ADS1281？

JIANG lI
Prodigy 20 points
Part Number: ADS1281

Can 1281 be powered by a single supply, such as AVDD=5V, AVSS=GND, VREFP=4.096V, VREFN=GND. If possible, is the analog input range still from VREF/2  to - VREF/2? At this time, can it be from positive 2.048V to  negative 2.048V?

  • +1
    TI__Mastermind 46590 points

    Hello Jiang,

    Yes, the ADS1281 can be powered from a single supply as you have described.  Below is a marked up Figure 56 from the datasheet that shows how to do this.

    You can still get the full +VREF/2 to -VREF/2 range, but the input voltages relative to ground (DGND=AVSS) must now be offset by AVDD/2=+2.5V.

    For positive full scale, +2.048V differential:

    AINP=2.5+1.024=3.524V

    AINN=2.5-1.024=1.476V

    Vin-diff=AINP-AINN=3.524-1.476=+2.048V

    For negative full scale, -2.048V differential:

    AINP=2.5-1.024=1.476V

    AINN=2.5+1.204=3.524V

    Vin-diff=AINP-AINN=1.476-3.524=-2.048V

    In all cases, the voltage on the inputs referred to DGND=AVSS must always be positive, but the differential voltage can be positive or negative.

    Regards,
    Keith Nicholas
    Precision ADC Applications

  • 0 in reply to Keith Nicholas
    Prodigy 20 points

    Thanks for your reply.