Effective Application of EMC Design Guidelines

Many of the worst printed circuit board designs we've encountered have been the direct result of someone's attempt to comply with EMC design guidelines. Good circuit board design is not a matter of complying with as many design guidelines as possible. It's much more important to comply with the few guidelines that are critically important in your application. Recognizing the critical guidelines will require a basic ability to identify the potential sources, antennas and coupling paths in your design.

Since no individual is likely to be an expert in circuit design, layout and EMC; it is important to get the right people together in the early development stages for an EMC Design Review. During this review, information about the electrical, physical and functional product specifications are shared with the EMC engineer. The EMC engineer can then provide advice regarding critical aspects of the design and recommend EMC guidelines that are both appropriate and important for the board being reviewed. It is best to conduct the EMC Design Review before the first board layout, since this is the best opportunity to "get it right" before many design decisions become irreversible. Another EMC Design Review should be held as soon as the first draft of the board layout is available. Frequent reviews throughout the design process are recommended.