Thermal management is one of the most important aspects of designing power supplies. This is especially true in the automotive environment where converters must operate in high ambient temperatures and enclosed spaces. This paper provides guidance to the designer that will make the task of thermal management proceed somewhat more smoothly.

The goal of thermal management is to keep the maximum junction temperature of the device at or below a safe value. This safe value is stated in the data sheet under the "Absolute Maximum" specification section as shown in the example of Figure 2-1.

Figure 2-1 Maximum Junction Temperature Specification

This will usually be 125°C or 150°C for an automotive qualified device and is called T_J-max. A good thermal design will keep the converter temperature below this value under all operating conditions.