Design considerations for power applications of surface mount technology

This paper discusses some design considerations associated with power electronic applications of Surface Mount Technology (SMT). Surface mount solder joints provide mechanical support as well as electrical continuity. In power applications using only surface mount components, the transformers and power switches are relatively large components supported only by solder joint interconnections. To effectively manage heat dissipation in a high density power converter design, encapsulation with a thermally conductive material may be required. Expansion of this encapsulating material with temperature places additional stress on SMT power component interconnections. The purpose of this paper is to alert designers to the additional development work that may be necessary when surface mounting large power components in encapsulated environments.