Editing question to add details:
The "analog resources" are programmable DACs which I described as voltage sources on the original question. The speed is not critical as the circuit intended to control switches for a DC bench measurement (I can spare 10s of seconds if needed). The digital outputs don't need to drive "heavy" loads, but digital switches, so the current should be around 1uA or less. I was very conservative on the original question and I believe the tri-state zone of the switches I need to control is probably around 2.25v to 3v, so anything < 2.2v should be a logic 0 and anything > 3.1v should be a logic 1. The idea I have in mind is to use a low voltage comparator with voltage dividers at the inputs.
I need some suggestions to solve my problem without complications. I have 3 analog resources which can force voltage anywhere from 0 to 5v. I need 4 digital signals which logic 1 is >=3.3v and logic 0 is <= 0.5v.
I cannot use microcontrollers. Only those 3 lines to convert to 16 different binary states. I was thinking an ADC, where 2 resources are used for supplies and the last resource for input, but I don't know if this is doable.
Ideally, if I had another resource then my problem would be solved, but I don't have it and the solution is limited to those 3 analog voltage resources. Thanks!