Application Information
96
SLES141B—August 2007
TVP5146M2PFP
5.2
Designing With PowerPAD
t Devices
The TVP5146M2 device is housed in a high-performance, thermally enhanced, 80-terminal PowerPAD
package (TI package designator: 80PFP). Use of the PowerPAD package does not require any special
considerations except to note that the thermal pad, which is an exposed die pad on the bottom of the device,
is a metallic thermal and electrical conductor. Therefore, if not implementing the PowerPAD PCB features, the
use of solder masks (or other assembly techniques) may be required to prevent any inadvertent shorting by
the exposed thermal pad of connection etches or vias under the package. The recommended option, however,
is not to run any etches or signal vias under the device, but to have only a grounded thermal land as explained
in the following paragraphs. Although the actual size of the exposed die pad may vary, the minimum size
required for the keep-out area for the 80-terminal PFP PowerPAD package is 8 mm
× 8 mm.
It is recommended that there be a thermal land, which is an area of solder-tinned copper, underneath the
PowerPAD package. The thermal land varies in size, depending on the PowerPAD package being used, the
PCB construction, and the amount of heat that needs to be removed. In addition, the thermal land may or may
not contain numerous thermal vias depending on PCB construction.
Other requirements for using thermal lands and thermal vias are detailed in the PowerPAD
t Thermally
Enhanced Package technical brief, TI literature number SLMA002, available via the TI Web pages at URL
http://www.ti.com.
For the TVP5146M2 device, this thermal land must be grounded to the low-impedance ground plane of the
device. This improves not only thermal performance but also the electrical grounding of the device. It is also
recommended that the device ground terminal landing pads be connected directly to the grounded thermal
land. The land size must be as large as possible without shorting device signal terminals. The thermal land
may be soldered to the exposed thermal pad using standard reflow soldering techniques.
While the thermal land may be electrically floated and configured to remove heat to an external heat sink, it
is recommended that the thermal land be connected to the low impedance ground plane for the device. More
information can be obtained from the TI Recommendations for PHY Layout applicaton report, TI literature
number SLLA020.
PowerPAD is a trademark of Texas Instruments.