Radiated Immunity

This month’s column is the last of three parts devoted to designing, testing, and EMC immunity evaluation of multilayer PCBs containing analog circuitry.

Most EMI issues are caused by a resonance that is excited somewhere in the system. It may be a resonance of a cable acting as an antenna or a heatsink energized by the power electronics switches bolted to it, becoming a good radiator. In this article, we look at the indicators that signal the presence of structural resonances and provide techniques for fixing the EMI issues. Practical case studies are presented to demonstrate the techniques.

Implementing a process of EMC compliance for a specific project is much more than simply ensuring that the design engineers follow a long list of “do’s and don’ts” in the form of EMC design rules. Following this process will reap benefits when EMC performance is evaluated at the end of the design process.

This two-part article provides an overview of current automotive EMC standards and the intricacies of chamber testing automotive systems and components.

This is the second of three articles devoted to the design, test, and EMC immunity evaluation of multilayer PCBs containing analog circuitry.