Split Power Plane - placement?

[mspagon]

I have a mixed signal board with +5 / -5 split planes.



How important is it that my capacitors (that are connected to -5 and +5 used for decoupling and stuff) fall directly between the split plane so that each plate is above the corresponding plane? Can the cap be placed anywhere? What if they are reversed and above the wrong planes?

Can the split plane be separated anywhere underneath my op amp as long as my power rails are a minimum distance to those planes?

Extra: What devices if any, should I avoid placing on the bottom layer directly underneath an op amp on the top layer?

Thanks all.

 

[FvM]

I think, the decoupling capacitors will be connected between +5 or -5 and ground plane.

For high speed design, I expect smaller ceramic caps (e.g. 100 nF) near to the component supply pins and larger capacitors "anywhere" else.