Description of the New Circuit
A brief description of the assembly, product, or sub-system for which this printed circuit board or PCB is currently in development for.
Conductor Layout Guidelines
Multi-layer Printed Wiring Boards
A multi-layer board should be used with internal conductor layers. Each layer should be separated by a power or ground plane. Every available square inch of the printed circuit board, which does not contain circuits or conducting runs, should be ground plane. If the circuit density is too high, the density must be reduced in order to create more ‘real estate’ for the ground plane. This will help to insure a uniform dielectric field for the conductors, thereby minimizing capacitive or electric coupling and the interaction of electric fields between the circuits located on the PCB.
USE the Ground Plane Liberally
It has been shown that analog-to-digital coupling noise is reduced by at least 30 dB if regions between analog signal traces are filled with copper and then electrically attached to the analog ground plane.
Conductor Layers (a.k.a. Signal Traces)
Adjacent conductor layers (whether analog or digital) should ‘run’ perpendicular to each other and cross at right angles. This will minimize parallel runs and subsequently reduce crosstalk and interference. Adjacent is where each pair of layers is assumed to be sandwiched between power and/or ground planes.
Power and Ground Conductors (Supply Leads)
Power supply and ground leads should be heavy and well located. The supply and ground-return traces must be routed in such a way as to achieve maximum (horizontal) isolation from the other. The supply and ground-return leads should not cross one another on the different layers of the PCB.