Abstract: A packaging system for a high current, low voltage power supply. The power supply uses bare die power FETs which are directly mounted to a thermally conductive substrate by a solder attachment made to the drain electrode metallization on the back side of the FETs. The source electrode and gate electrode of each FET are coupled to the circuitry on an overhanging printed circuit board, using CSP solder balls affixed to the front side of the FET die. The heat generated by the FETs is effectively dissipated by the close coupling of the FETs to the thermally conductive underlying substrate. High interconnect densities are achieved through the use of a multilayer printed circuit board. This high interconnect density, with the addition of a magnetic core element, allows the power supply packaging system to incorporate transformer windings for an isolation transformer or an inductor.

Abstract: The invention provides arrangements to facilitate surface mounting of subassembly boards on a motherboard with reliable, high conductivity interconnection. In accordance with the invention, the subassembly interconnection arrangement is composed of separate power and sense connector arms formed on one or more base headers. The arrangement interconnects and supports the subassembly board on the motherboard surface. Each power arm advantageously comprises a plurality of split-based mounting lugs secured to the arm in a coplanar configuration. Each sense connector arm preferably comprises a plurality of connector pins secured to the arm in a coplanar configuration. Embodiments are disclosed for vertical and horizontal surface mounting.

Abstract: A mounting structure for a semiconductor die that reduces die attach strain within the die attach material without sacrificing the electrical and thermal characteristics of the package. In one embodiment, the mounting structure comprises a die attach metallization layer, a solder mask, and a layer of die attach material. The solder mask forms a solder pattern over the top surface of the die attach metallization layer. The solder pattern covers a portion of the die attach metallization layer to create multiple exposed areas of the die attach metallization layer. Each exposed area is separated by the solder mask and is located under the semiconductor die when the semiconductor die is secured to the mounting structure. A layer of die attach material covers the solder pattern and fills in each one of the exposed areas to form a semiconductor die mounting surface. In another embodiment, the die attach metallization layer is divided into multiple, spaced-apart die attach pads that are electrically coupled together.

Abstract: A mounting structure for a semiconductor die that reduces die attach strain within the die attach material without sacrificing the electrical and thermal characteristics of the package. In one embodiment, the mounting structure comprises a die attach metallization layer, a solder mask, and a layer of die attach material. The solder mask forms a solder pattern over the top surface of the die attach metallization layer. The solder pattern covers a portion of the die attach metallization layer to create multiple exposed areas of the die attach metallization layer. Each exposed area is separated by the solder mask and is located under the semiconductor die when the semiconductor die is secured to the mounting structure. A layer of die attach material covers the solder pattern and fills in each one of the exposed areas to form a semiconductor die mounting surface. In another embodiment, the die attach metallization layer is divided into multiple, spaced-apart die attach pads that are electrically coupled together.