On 8/8/05 19:31:50, Brad wrote: > Signal, Plane, Plane, Signal. OR Signal, Signal, Signal, Signal. for 4 > layer examples. NOT Signal, Signal, Plane, Signal. > > Now without knowing how many signals you may have to route internally, > could you do mixed signal/plane(polygon) internal layers? And try to > roughly balance the copper coverage between the two internal layers?
That's what I often do. Like when you have a few heavy traces for large currents -- they are often in areas that are not so dense as to require traditional power and ground layers, but the additional layers help in routing these large traces. So my general setup is to have the two mid-layers filled with polygons and large traces. In densely populated small-signal areas, they are usually grounds and supplies. In high current areas, they are usually high-current traces (which may or not be ground or supply, and usually are polygons). In the end, it works out to what Brad says: the outer layers carry small signal traces, and the inner layers are pretty much filled with copper... kind of naturally :) Gerhard ____________________________________________________________ You are subscribed to the PEDA discussion forum To Post messages: mailto:[email protected] Unsubscribe and Other Options: http://techservinc.com/mailman/listinfo/peda_techservinc.com Browse or Search Old Archives (2001-2004): http://www.mail-archive.com/[email protected] Browse or Search Current Archives (2004-Current): http://www.mail-archive.com/[email protected]
