I am reviewing a 6 layer board that has analog signals on the left and right side of the board.
I have always read that analog circuitry should be grouped together for easy plane segmentation. However in the real world that is not always possible, such as this case...
The image labels, in text, where the analog circuitry, power circuitry, and star grounding point are. The star grounding point is where the the Vin/GND terminal block is.
The layer shown is the internal ground plane, with the darker green area being the analog plane and the whiter/lighter green area being the digital ground. All of the analog input traces are covered by the AGND plane area.
Is this is valid grounding scheme if the bottom layer is a complete digital ground pour?
Technically I know the grounding for analog and digital should be on the adjacent layer to the signals, but this is a basic relay output and analog input (8 bit) board and not high speed.