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
• Improving the thermal coupling of the component to the PCB by soldering the exposed thermal pad
• Introducing airflow in the system

For more details on how to use the thermal parameters, see the application notes: Thermal Characteristics Application Note (Thermal Characteristics of Linear and Logic Packages Using JEDEC PCB Designs Application Report), and (Semiconductor and IC Package Thermal Metrics Application Report).

The TPS6214X is designed for a maximum operating junction temperature (T_J) of 125°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. Since the thermal resistance of the package is fixed, increasing the size of the surrounding copper area and improving the thermal connection to the IC can reduce the thermal resistance. To get 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. Experimental data, taken from the TPS62140 EVM, shows the maximum ambient temperature (without additional cooling like airflow or heat sink), that can be allowed to limit the junction temperature to at most 125°C (see Figure 9-38).