Due to layout restrictions I may have to have digital signal at one side of the board, and analog signal at the other side. I used to separate them dedicating parts of the board for each, but not this time.
- Board thickness: 1.6 mm
- Layers: 2
- Digital signal: 3.3/2.5/1.2 V LVTTL, up to ~30 MHz
- Analog signal: audio ±1.5 V (output of op-amps in voltage follower mode powered from ±12 V), mostly human ear hearing band
I am worried if quality or integrity of one signal will be negatively affected by the signal on another side of the board.
Are my apprehensions having a reason to exist, or I am over-complicating things? Should I make 4-layer board with ground layer as "padding" between digital and analog?
In general, what should I be aware of if I will decide to continue with such design?
@MichaelKaras: Not possible to separate at this time, that's why I ask this question. I have to place audio jack in the middle of digital logic because putting it in other places of PCB will simply make it not accessible outside of chassis. Audio signal will be fed to the jack through airwires, thus in general there will be just several pads of analog signal, but there're digital wires at another board's side which I afraid may suffer.