Achieve Compatibility in Thermal Design

By DE Editors

Flomerics has introduced an online guide that integrates thermal andEMC design to help designers identify and resolve system-levelelectromagnetic compatibility (EMC) issues.The guide recognizes that most new electronic products failfirst-time EMC testing because manufacturers don’t usually evaluatesystem-level EMC performance prior to the prototype phase.

The first step in the new step-by-step process follows the developmentof a thermal budget, which is common practice in most teams involved inelectronic design. The new approach departs from common practice inusing analogous methods to simultaneously develop a full-spectrumshielding requirement. The shielding requirement is created by accruingEMC requirements that are set by regulatory bodies, the customer andinternal and external emissions susceptibility considerations.

At this point, the engineers responsible for thermal design usuallylack detailed information so they create a relatively rough thermalmodel of the entire system. The new approach departs from normalpractice in using the thermal model to initiate an EMC simulation ofthe enclosure in order to identify resonances and determine which areasare sensitive from a shielding effectiveness standpoint.

The next stage of thermal management typically involves refining thesimulation model. “Compact” models used in the simulation up to now maybe replaced by more detailed and accurate models. The same refinementsthat are added to the thermal model make it possible to start lookingat the effect of the physical layout on radiated emissions. A moredetailed system-level model helps engineers quickly zero in on problemareas such as a heat sink that acts as an antenna and how the structureof the box contributes to emissions.

As the design process continues, mechanical engineers perform detailedthermal analysis of components that have been identified as potentialproblems. At this stage, engineers make adjustments to optimize thedesign from a thermal standpoint and, at the same time, determine theeffect of design changes on EMC. For example, the effects of groundingheat sinks may be investigated and PCB shields may be introduced toreduce radiation from high-speed components.

According to Flomerics, combining thermal and system-level EMC design withinan integratedanalysis environment streamlines design collaboration betweenmechanical and EMC engineers enabling early identification and remedyof system-level EMC compliance issues, and drastically reducing therisk of late-cycle compliance failure.

For more information, visit Flomerics’ Web site. The guide may be found at: www.floemc.com/stepbystep