With the smallest footprint currently available, the 4-bump micro SMD has a total surface area of roughly 0.8mm 2 . Thermal Performance and Heat Dissipation Small size does not imply reduced or relaxed performance parameters. The miniature size of the micro SMD often provokes the question about thermal performance. Heat dissipation of the micro SMD is on par with the SOT23, the dominant package in portable communications. To get the optimal thermal performance a copper LLP thermal land matching the dimensions of the DAP should be located directly under it.
Thermal vias conduct heat from the surface of the PCB to the ground plane.
Vias are typically placed in a grid pattern. The vias should be plugged to avoid solder wicking during assembly. If copper plating cannot plug the vias, the thermal vias can be tented with the solder mask on the PCB top layer. A void in the solder paste will have a negative affect on heat dissipation. There are three ways to dissipate heat conduction, convection and radiation.