DM355 - How many layers are required for PCB design?

This is a very broad question.  The answer depends of course, on what connections need to be made to the DM355.  We have an example BGA escape using 3 signal layers that will connect to every pin, so if you wanted to use the entire processor, 3 signal layers + 2 (minimum) power planes would be a 6 layer design (no point in using only 5 layers of a PCB since you have to pay for 6 anyway).

So the answer is 6 layers if you want to use everything, however I've never seen a customer design that uses every pin.  A good PCB designer could probably get this down to four layers for a typical application that doesn't use every pin.

I will send this design out later today.  I tried to attach it, but the Twiki page I used to have it on is down, so I'll need to get it from it's original designer.

I hope this helps!