Problem with Vref of AD7623

Hi,

      We utilize the internal reference voltage when applying the AD7623. According the datasheet of AD7623, the internal reference voltage is 2.048V, which is produced by the 1.2 V voltage of REFBUFIN pin.

     However, during the test, we test the voltage of REFBUFIN pin is 1.1489V and the voltage of REF pin is 1.864 V, which have a big difference with characteristic of datasheet. Addition, the datasheet only has a typical value of internal reference voltage.

    So, is the situation of the introduced above reasonable?

Thanks.