The THS3491 is available in a thermally-enhanced PowerPAD integrated circuit package. These packages are constructed using a downset leadframe on which the die is mounted, as shown in the (a) and (b) sections of Figure 10-10. This arrangement results in the lead frame that is exposed as a thermal pad on the underside of the package, a shown in Figure 10-10(c). Because this thermal pad directly contacts the die, achieve efficient thermal performance by providing a good thermal path away from the thermal pad. Devices such as the THS3491 have no electrical connection between the PowerPAD and the die.

The PowerPAD integrated circuit package allows for assembly and thermal management in one manufacturing operation. During the surface-mount solder operation (when the leads are soldered), the thermal pad can be soldered to a copper area underneath the package. By using thermal paths within this copper area, heat is conducted away from the package into a ground plane or other heat-dissipating device.

The PowerPAD integrated circuit package represents a breakthrough in combining the small area and ease of assembly of surface mount with the, heretofore, awkward mechanical methods of heatsinking.

Figure 10-10 Views of Thermally Enhanced Package

Although there are many ways to properly heat sink the PowerPAD integrated circuit package, see Section 10.4.1.1.1 for the recommended approach.