Maintaining Electromagnetic Compatibility (EMC) Through Design for Fabrication and Assembly of Printed Circuit Boards (PCBs)

Recent regulations have demanded that electronics manufacturing companies control emissions from their products and the susceptibility of their products to emissions from other products. In addition, unexpected product failure and the ever-present demands of technology are also forcing the electronics industry to face the need to maintain electrical integrity. Our investigations into high-speed design techniques have shown three major causes of failure: emissions from interconnecting conductors; poor PCB layout and lack of technical knowledge in electromagnetic compatibility (EMC). Catching these kinds of electrical integrity problems early in the design phase allows designers to take timely action without jeopardising project time scales. The work reported here presents design for manufacturing guidelines and rules to maintain electrical integrity in printed circuit boards (PCBs). Currently, a common method for handling EMC is through compliance testing of the final product. Similarly, noise budget is measured on finished prototypes. Since product life cycles are reducing, dealing with EMC late in the design cycle is undesirable. The cost of fixing may also be higher at a final stage because only a few options are available to correct the problem. A ‘find and fix’ approach is no longer acceptable anymore. More and more companies are facing or will soon be facing EMC and electrical integrity issues. The majority of analysis tools available today are targeted toward simulation engineers. Such tools are not easy to use and are dependent on the availability and accuracy of complex simulation models. Moreover, they also tend to be ineffective on how to correct potential EMC problems.