Steady-State and Transient Thermal Modeling For a SAW Duplexer

A time-domain thermal model is developed for a SAW duplexer mounted on a laminate and evaluation board (EVB). The simplified model consists of a 'dissipated power' source in parallel with a thermal resistance and a thermal capacitance. The dissipated power in the monolithic duplexer die is allowed to vary with output temperature as dictated by the filter TCF. Thermal resistance is calculated using a combination of self-heating measurements on the duplexer + laminate + EVB and simulations used to determine dissipated power in the laminate and matching components. Thermal capacitance is estimated using material properties and duplexer die layout. Once the various simulation parameters are determined, it is demonstrated that both steady-state and transient thermal simulation results agree reasonably well with measurement made with an Infrared (IR) camera.