I am unable to find a 20 bit DAC that's small enough, daisy-chaineable, with single supply, etc.
I'm thinking of using two 10 bit DACs and add their outputs with the right weighting (1:1024).
I think I know how to do this with voltage output DACs but am unsure how I can do it with the AD5439, mainly because it has the feedback resistor output and I don't know what to do with it when summing currents.
If there was one output outputting the current I could just connect them in the feedback loop resistors of the output Current to Voltage converter.
My space is very limited; I hardly have space for ONE external OpAmp and 3 resistors so I'm not looking for "by the book" solutions.
Alternatively, are there any SMALL 10-12 bit, Buffered Voltage Output, daisy-chaineable, external reference, single supply (~5V) DACs?
Ideally pins would be: V+, GND, Data In, Data Out, CLK, REF, Out.