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AD7176-2 REFOUT while using an external reference

Hi,

I am designing a board to read +-10V signals using the AD7176-2. I want to drive it by a AD8475 as on page 24, but to be able to use a single 5V supply, I will use an ADR444 supplying 4.096V as an external reference.

Now I am unsure about the state of REFOUT, and I cannot really find this specific part of information in the datasheet.

The example circuit on page 24 of the datasheet suggests that although an external reference is used, there is still 2.5V on the REFOUT pin. On the other hand, on page 27 of the datasheet it says:

The internal reference is output on the REFOUT pin after the REF_EN bit in the ADC mode register is set

So to be specific, here is my question:

When using an externel reference voltage, i.e. REF_EN is NOT set, will the 2.5V internal reference voltage still be available on the REFOUT pin?

Many thanks in advance,

DRies

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  • Hi Johnny,

    thank you for your reply. I don't understand, why Fig. 30 is in the datasheet then, as it is obviously wrong. Either, the whole external reference part is not used at all, or the common mode adjustment of the AD8475 is defunctional. Any idea which is the case?

    Cheers,

    DRies

Reply
  • Hi Johnny,

    thank you for your reply. I don't understand, why Fig. 30 is in the datasheet then, as it is obviously wrong. Either, the whole external reference part is not used at all, or the common mode adjustment of the AD8475 is defunctional. Any idea which is the case?

    Cheers,

    DRies

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