Datasheet

General PowerPAD Design Considerations
2-8
Evaluation Module Layout
4) Connect all holes to the internal ground plane.
5) When connecting these holes to the ground plane, do not use the typical
web or spoke via connection methodology. Web connections have a high
thermal resistance connection that is useful for slowing the heat transfer
during soldering operations. This makes the soldering of vias that have
plane connections easier. In this application, however, low thermal
resistance is desired for the most efficient heat transfer. Therefore, the
holes under the device package should make their connection to the
internal ground plane with a complete connection around the entire
circumference of the plated-through hole.
6) The top-side solder mask should leave the terminals of the package and
the thermal pad area with its five holes exposed. The bottom-side solder
mask should cover the five holes of the thermal pad area. This prevents
solder from being pulled away from the thermal pad area during the reflow
process.
7) Apply solder paste to the exposed thermal pad area and all of the IC
terminals.
8) With these preparatory steps in place, the IC is simply placed in position
and run through the solder reflow operation as any standard
surface-mount component. This results in a part that is properly installed.
Correct PCB layout and manufacturing techniques are critical for achieving
adequate transfer of heat away from the PowerPAD IC package. For more
general information on the PowerPAD package and its thermal characteristics,
see the Texas Instruments Technical Brief,
PowerPAD Thermally Enhanced
Package (SLMA002).