I'm using a dual digital pot IC controlled with an SPI interface. Each pot goes to a different op amp on the pcb to calibrate two different voltages. Since both pots are in the same package, how big a deal is it if the pots are far from the op amp feedback loops? Typically, the amp resistors should be as close as possible to the amp to reduce noise. The voltages ultimately feed into 12-bit ADCs, so with the resolution being relatively low, can I get away with this as is?
Also, how do the SPI lines affect the DC analog readings if at all? If I keep the digital traces away from the analog values with a ground pour in between will that suffice, or should they be isolated in some other manner?
I'm looking to get the most accurate/stable reading possible. Currently going with a four layer pcb, but may have to reduce it to two.
Edit: images added