Implementation of integrated circuits in low-profile and fine-pitch surface-mount packages typically requires special attention to power dissipation. Many system-dependent issues such as thermal coupling, airflow, added heat sinks and convection surfaces, and the presence of other heat-generating components affect the power-dissipation limits of a given component.

Three basic approaches for enhancing thermal performance are listed below:

• Improving the power dissipation capability of the PCB design, for example, increasing copper thickness, thermal vias, number of layers
• Introducing airflow in the system

For more details on how to use the thermal parameters, see the application notes: Thermal Characteristics Application Note (SZZA017), and (SPRA953).

The TPS62903 is designed for a maximum operating junction temperature (T_J) of 150°C. Therefore, the maximum output power is limited by the power losses that can be dissipated over the actual thermal resistance, given by the package and the surrounding PCB structures. If the thermal resistance of the package is given, the size of the surrounding copper area and a proper thermal connection of the IC can reduce the thermal resistance. To get an improved thermal behavior, it is recommended to use top layer metal to connect the device with wide and thick metal lines. Internal ground layers can connect to vias directly under the IC for improved thermal performance.

If short circuit or overload conditions are present, the device is protected by limiting internal power dissipation.

The device is qualified for long term qualification with 150°C junction. For more details about the derating and life time of the HotRod package, see the application note: SPRACS3.