Split/Mixed Planes

[Tom]

We are using PowerPCB V4.0. We are experiencing a problem with Split/Mixed planes. Maybe the problem existed in other revisions but we used CAM Planes exclusively until just recently.

We have a design with 2 planes. One GND plane and one PWR plane. But the engineer wants a smaller GND island on the PWR plane. When we run DRC Plane Checks we get 1,700 errors on the PWR Plane layer because GND is not tied to every pin on that layer. We have full continuity on the GND layer. Is this the way Split/Mixed Plane technology works or am I missing something?

[Mark Larson]

yup, the fix is simple, when doing a plane check go into setup, uncheck same layer connectivity

the check is telling you that all pins on this particular layer in GND net are not connected to this particular layer

[Tom]

Thanks Mark,

That was the problem. You would not believe what we went through to try and figure that out. We switched the plane layers to regular "Copper Pour" and then we lost the Impedance Control indicator. It indicated impedance levels of Zero because we took away the reference plane. The we switched back to CAM planes to get the impedance working again but the planes had too many splits to accurately use CAM Planes. Now that we know what the problem was, we're switching back to Split/Mixed Planes.

See what happens when you use a feature for the first time.