I have a multilayer PCB (10 layers) with analog preamp on the top and digital parts (6 * AD726) on the bottom side.
I have a GND for the analog preamp in inner1 layer and another GND plane on the int8
All VDD1-VDD2 and VIO supply rails are on inner 6 layer.
All the ground planes are sharing in one point on the power supply connector. My question is for the VDD1 (analog supply rail of the ADC) and external reference+buffer (which are also on the bottom side) do I rather use the "analog" ground in inner1 or the digital one in inner8 ?
In fact, I wanted to have a ground plane for all components of the bottom layer : reference + buffer + ADC, but since there are analog and digital, I'm wondering if it's the good way ?
On the AD7626, which GND pins needs to be connected to the "digital" GND plane ? and another to the analog GND plane ? or can leave this as is it ?