pcb multilayer routing

hi everyone,

for 4 layers what type of vais we can use?
i have read that three types of vais are there (blind,buried,standard)..is this neccessary to use in 4 layer
and can anyone explain how to route in 4layer,also to create gerber files what are all the layers should be enabled.......
am using orcad 9.1 suite
can anyone send tutorials regarding multilayer....

Hi,

The types of vias you mentioned depends on which layers the components to be interconnected are present. A blind via starts on the top layer and ends before the bottom layer( You cannot see its other end hence blind). A buried via starts after the top layer and ends before the bottom layer. It is completely buried inside the layers. A through hole via starts on the top layer and ends on the bottom layer.

The requirement of via depends on your design. Say your design is a simple one with circuit on top layer, gnd plane in the next layer and VDD plane in the third layer then you can use a through hole via with clearances depending on electrical connectivity. If the deisgn is complex with buried components at multiple layers, you may have to use all the layers.

Generally, the cost of the PCB goes up if you go for blind or buried vias.

Most of the CAD tools differentiate layers by the colour of the routing track. You can check with orcad GUI. There will be a dropdown select menu where you can switch between layers for routing.

While routing be thorough with thermal dissipation issues, EMI compliances, etc..

For help write to sristykrishnaprasad@hotmail.com

Choose some PCB design program and explore it you will get all of you answers easily by practical (by doing and learning)there are many software are available some of them even offer there demo program to ovulate.
You can check Cadsoft eagle good for novice as well as for professionals.