Thermal management is becoming more important as the density of electronic components in modern printed circuit boards (PCBs), as well as the applied power, continue to increase. Both factors lead to higher temperatures of individual components and of the entire assembly. However, every electrical component in an assembly has to be used within its prescribed operating temperature limits due to its material properties and reliability aspects. This application note explores how the overall thermal resistance of the component and the PCB, including its capability to dissipate heat to the environment, are mainly determined by PCB design and environmental conditions.