A Simple Model for Transient Thermal Behavior of Integrated Circuit Package Systems for Use in Determining a Thermal Design Power Available to Purchase

The ever increasing power dissipation requirements of electronic components and the need to provide reliable, cost-effective thermal solutions requires the thermal engineer to accurately understand the component’s thermal design power (TDP). The TDP is impacted not only by the power-performance characteristics of the component architecture, but also by the inherent thermal characteristics of the cooling solution. A suitable TDP definition thus requires a clear understanding of the transient thermal response (resistance and capacitance) of the cooling solution. In this paper, a simple electrical analogy impedance network model that resembles the component with cooling solution is developed. Correlation models to predict the resistance and capacitance for this impedance network are built based on easily available parameters such as heat sink mass, surface area, specific heat etc. The accuracies of these models are validated experimentally with data collected on a PCB with several different thermal solutions. Development of these correlation models eliminates the need for complex time consuming transient experiments to characterize the system thermal characteristics like capacitance, which allows faster, more realistic TDP definitions and ability to analyze multiple thermal designs quickly and accurately.