Influence of connections as boundary conditions for the thermal design of PCB traces

The thermal design of a printed circuit board (PCB) requires a correct estimation of the temperature of each component that is part of it to guarantee the lifetime of the board. The literature presents different approaches for the prediction of the temperature distribution on the PCB, which considers both the contribution of the number and thickness of the copper layers and the quantity of current that is fed. The simulations and fitting equations usually calculate the temperature increase without considering the effect of connections, vias, or components on the trace, but they are actually fundamental contributors to the temperature distribution in the board, the position and the value of the hotspot. Some examples on trace and connection to the trace will highlight this concept and prove that these boundary conditions can´t be ignored for a proper, optimized thermal design of PCB traces.