Most sources on the internet discuss routing signals over a split power plane and how to do this properly. The main solution here is to create a short return current path. I'm wondering whether routing signals over a split power supply plane (not ground plane) will have any noticeable effect on the signal integrity and if i should take measures.
My situation:
4-layer PCB:
- Top layer: signal
- Internal plane: splitted ground (analog/digital)
- Internal Plane: splitted power supply plane (3.3V digital and 3.3V analog are relevant in this case)
- Bottom layer: signal
I'm routing a few clock signals at the bottom layer starting from the digital section to the analog section. The signals will cross the power plane split between the digital and analog section (gap is 0.5mm wide). I will provide a solid current return path on the ground plane (bridge between digital and analog) so return currents shouldn't be an issue.
The clock signal is just above 12MHz, the traces are 0.2mm wide and a maximum length of 13.4cm. The traces are terminated with a series resistor.
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