Stack-up related question

[manishyamdagni]

Dear All,

Currently Iam working on the design that contains 10 layer. I kept both the outer layer as power layer and rest of 8 layers are routing layers. My question is what happens if we keep 8 routing layer continuously(without GND or VCC in between), and upto how much routing layer can kept continuously?

Thanks to all.

 

[v_kumar]

1) all the layers should be Symmetric
2) when two or more signal routing layers come adjecent we cannot run routing parallel to each other they can cross at 45 degree.
3) When having planes in between signal will allow you or gives freedom of routing the traces vertical or horizontal
4) Proper return path for all the signal (common mode) is proper since referenced to its adjecent plane.

You can read the High speed design Guidelines from Black Magic... for the above.