Complete PCB Design Using OrCAD Capture and PCB Editor

Defining the Layer Stack-Up for Split planes

As discussed in the first example, it is a good idea to have the board constraints defined prior to starting the board layout. Items to consider are the board technology, board size constraints, noise and shielding requirements, part placement restrictions, the number of Power and Ground planes and Signal layers, and trace width and spacing requirements.

The voltage and current constraints are similar to those of the analog design, except that the analog parts should be segregated from the digital parts on the board. In the first analog design example, we used four planes for V+, V−, and ground. A similar approach could be taken here, but in this example we use one plane for V+, V−, and VCC, and one ...