For a mixed signal PCB with DACs, ADCs, MCUs and multiple analog opamp circuits. With +/-15V to power the opamps, 3.3V for all the digital stuff and a couple reference voltage rails (1.5V and 3V).
Can someone suggest a layer breakdown for a 4 Layer PCB? Obviously ground for one of the inner layers and I was also thinking in the digital part of the board I could make the second inner layer a 3.3v fill and then in the analog part I could leave it unfilled and run power traces (+/-15v and 1.5/3v ref) there. Is this a bad idea?
Edit: Forgot to mention components are on both sides of the PCB