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ADS7844: Can a four-chip ADC share a single REF3425 reference?

user6197310
Prodigy 170 points
Part Number: ADS7844
Other Parts Discussed in Thread: REF3425

The 32-channel voltage acquisition circuit uses 4 ADS7844. Can I share a REF3425 reference? If not, how can I handle it?
  • 0
    TI__Mastermind 24970 points

    Hello,

    A multi ADC circuit can share the same reference, but the voltage line needs to have a wide bandwidth on it.

    This may implemented with a Reference with an internal buffer, an external buffer op amp between the reference and ADCs, or an internal buffer in the ADC.

    The ADS7844 does not have an internal reference buffer.

    But the REF3425 does have an internal buffer, thus it should be able to support the load. The datasheet for the REF3425 does not give detailed information on the buffer though, a wide bandwidth buffer would be needed.  The current load vs voltage droop is given though, and from that I do suspect it will work.

    Regards

    Cynthia