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 heatsinks and convection surfaces, and the presence of heat-generating components affect the power-dissipation limits of a given component.

These three basic approaches enhance thermal performance:

• Improving the power dissipation capability of the PCB design.
• Improving the thermal coupling of the component to the PCB.
• Introducing airflow to the system.

The recommended device junction temperature range, T_J, is –40°C to 125°C. The thermal resistance of the 24-pin QFN, 4–mm × 4–mm package (RGE) is R_θJA = 34.1°C/W. The recommended operating ambient temperature range for the device is T_A = –40°C to 85°C. Use Equation 13 to calculate the maximum power dissipation, P_Dmax, as a function of T_A. In this equation, use T_J = 125°C to operate the device within the recommended temperature range, use T_J = T_TS to determine the absolute maximum threshold when the device might go into thermal shutdown. If the maximum ambient temperature of the application is lower, more heat dissipation is possible.

Equation 13.