In the data sheet for AD5545/AD5555 (rev. I), in the figure 22, there is a voltage regulator ADR03 connected by VIN to VREF of AD5545/AD5555. Is it an error? Or, maybe, there is some sense in this connection?
And, BTW, another question about this scheme. Does it allow both positive and negative VREFs and both positive and negative gains? It seems that it should, but I'd like to receive an exact answer.