Patent ID: 8217503

Claim:
A package structure for DC-DC converter, comprising: a high-side MOSFET chip ( 21 ) and a low-side MOSFET chip ( 22 ) respectively having a bottom drain electrode, a top gate electrode and a top source electrode; a lead frame having a first die pad ( 11 ) and a second die pad ( 12 ), the first die pad having a first portion and a second portion wherein said high-side MOSFET chip ( 21 ) being disposed on the first portion of the first die pad ( 11 ) with its bottom drain electrode electrically connected with the first die pad ( 11 ); a controller ( 40 ) disposed on the second portion of the first die pad ( 11 ) and being electrically connected with the top gate electrode of the high-side MOSFET chip ( 21 ); a conductive interposer ( 30 ) disposed on top of the second die pad ( 12 ) and at least a portion of the high-side MOSFET chip ( 21 ) and being electrically connected with the top source electrode ( 211 ) of the high-side MOSFET chip ( 21 ), wherein said interposer ( 30 ) does not cover the controller ( 40 ); wherein the low-side MOSFET chip ( 22 ) being disposed on the interposer ( 30 ) with its top gate electrode electrically connected with the controller ( 40 ) and its bottom drain electrode electrically connected with the top source electrode ( 211 ) of the high-side MOSFET chip ( 21 ), wherein the low side MOSFET chip extending beyond an edge of the conductive interposer hanging over at least a portion of the controller.