10.3 Thermal Considerations

The useful range of a driver is greatly affected by the drive power requirements of the load and the thermal characteristics of the device package. In order for a power driver to be useful over a particular temperature range the package must allow for the efficient removal of the heat produced while keeping the junction temperature within rated limits. The UCD8220 device is available in the PowerPAD integrated circuit package, HTSSOP, to cover a range of application requirements. The package has an exposed pad to enhance thermal conductivity from the semiconductor junction.

As shown in ⁽⁴⁾ in the Related Documentation section, the PowerPAD integrated circuit packages offer a leadframe die pad that is exposed at the base of the package. This pad is soldered to the copper on the PC board (PCB) directly underneath the device package, reducing the R_θJA down to 37.47°C/W. The PC board must be designed with thermal lands and thermal vias to complete the heat removal subsystem, as discussed in ⁽³⁾ in the Related Documentation section.

Note that the PowerPAD integrated circuit package is not directly connected to any leads of the package. However, the PowerPAD is electrically and thermally connected to the substrate which is the ground of the device. The PowerPAD integrated circuit package should be connected to the quiet ground of the circuit.