Preffered stackup and planes?

[pavjayt]

I have designed a 4-layer board which is 96% analog and is about 242mmx70mm in size. It has ±5VDC power supply. The current consumption on each rail shouldn't be more than 500mA, no ground pour on top layer
Having a bit of a hard time deciding on which stackup I should go with. There are 8 identical sections of schematic here which each section input being ~50MHz analog that is connected to a buffer and goes through a 10MHz LPF. Here are what I came up with
Option1: Split power plane on Ly3 as below with 0.5mm gap between split planes and a few traces crossing the splits

Stackup-

Option2:- Solid power planes stackup as below

Option3: SOlid power planes stackup as below

Would appreciate any recommendations/suggestions
thanks

 

[pavjayt]

Anyone? I am leaning more towards option1 or option3....

 

[Pommie]

I'm assuming that this is how your 4 layers of a PCB are arranged. If so, why do you need any plane duplicating? Surely, a GND, 5V and two signal layers would make routing much easier.

Mike.

 

[pavjayt]

If we don't need 2 gorund planes, then option 3 should work with two power plane layers ( ± 5V) and bottom GND plane layer, while keeping all the power planes close to each other to keep noise low. Just wondering if 0.15mm of core separation is good enough between the two power planes.