My PCB makes use of an 8-channel DAC, the 8 outputs of which terminate at a 2x4 2.54mm pitch through hole header. I've attached a screenshot of the DAC circuit and indicative analogue output traces below. I've segmented these components as much as possible from other components on the board (4-layer board with SIGNAL-GND-VCC-SIGNAL stack); these components and traces are on the bottom side of the PCB. Note that the trace width and clearance parameters shown below are the default values in KiCAD; I've only laid them out as shown below to provide context.
A couple of questions/clarifications:
- What's the best way to minimise noise and potential coupling (with nearby digital signals) in these analogue traces? Should I run guard traces between each of the analogue traces, only connecting each guard trace to the common GND plane at the DAC?
- More broadly, how should I approach management of return paths?
- I've purposefully positioned the DAC (and associated components) on the very edge of the PCB. Am I better off moving these components closer to the header to minimise the analogue trace length, or is increased distance of the analogue circuit components from other/digital components more important?
- Is there a standard trace width and spacing I should consider for these traces? The current default is 0.254mm width with 0.254mm spacing/clearance.
Any input will be greatly appreciated as always!