Hello,
I am having issues running the DAC8812 on a single supply. I am working from the schematic in the datasheet (Figure 31) with this modification: AGNDA is connected to OPAMP IN+ and forced to a voltage using an external power supply, running on +3.3V supply.
AGNDA and OPAMP IN+ should be 1.65V for this single-supply application. The datasheet indicates that AGNDA, VREFA, IoutA, RFBA should all be separate from DGND, implying that this should work no problem.
When connecting a voltage to AGNDA using an external supply I am finding that up until ~0.4V there is no problem, however above this voltage the supply output current begins to climb dramatically. I can reach 1.65V however at that point the current is about 100 mA which defeats the purpose of using this circuit.
Do you have any comments on why a voltage applied to the AGNDA node has such a low-impedance to DGND?