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Integrate Thermal Pad on Two DPAK and D^2PAK Packages

IP.com Disclosure Number: IPCOM000033854D
Publication Date: 2004-Dec-30
Document File: 4 page(s) / 162K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that adds a copper or aluminum pad to the top side of the DPAK and D^2PAK packages. Benefits include dissipating heat from the top side of the packages.

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Integrate Thermal Pad on Two DPAK and D^2PAK Packages

Disclosed is a method that adds a copper or aluminum pad to the top side of the DPAK and D^2PAK packages. Benefits include dissipating heat from the top side of the packages.

Background

During heavy loads from the power MOSFET, not enough heat is removed from the DPAK and D^2PAK packages. Currently, the DPAK and D^2PAK package drain pad is on the bottom side of the package. This drain pad is soldered directly onto the printed circuit board; however, this makes heat dissipate down onto the printed circuit board, instead of the top side of the package where airflow is available. This is not sufficient because the power consumption on the voltage regulator and the power MOSFET will increase in future designs.

It is very difficult to add a heat sink or heat spreader on top of the current package; this would require a thermal interface and a retention mechanism, which add more complexity to the assembly process. The thermal impedance between the silicon, the case, and the heat sink is high due to the plastic molding space between the silicon and the heat sink. This reduces the cooling efficiency of the package (see Figure 1).

General Description

During the DPAK and D^2PAK assembly process, a copper or aluminum pad is stacked and mounted on the top side of the package, which is directly attached to the top of the silicon of the power MOSFET. This arrangement reduces the thermal impedance between the silicon, the copper/aluminum, and the top side ambient.

Both copper and aluminum have excellent power heat dissipation properties, however, copper is slightly better than aluminum. Also, the heat sink or heat spreader is more easily soldered on to the copper pad, which simplifies the manufacturing process. Cooling is enhanced by having a heat sink or heat spreader soldered directly on top of the DPAK and D^2PAK package. Combined with airflow, the disclosed method...