Patent ID: 7932588

Claim:
A semiconductor device including a DC-DC converter, comprising: a first die pad having a top surface and a bottom surface opposite each other, and a first lead used for inputting to the DC-DC converter; a second die pad having a top surface and a bottom surface opposite each other, and a second lead used for outputting of the DC-DC converter; a third die pad having a top surface and a bottom surface opposite each other, and a third lead; fourth leads used for supplying ground potential to the DC-DC converter; a first semiconductor chip disposed over the top surface of the first die pad, the first semiconductor chip including a high side MOSFET of the DC-DC converter, the first semiconductor chip having a first gate electrode pad, a first source electrode pad, and a first drain electrode, the first drain electrode being coupled to the first die pad; a second semiconductor chip disposed over the top surface of the second die pad, the second semiconductor chip including a low side MOSFET of the DC-DC converter, the second semiconductor chip having a second gate electrode pad, a second source electrode pad and a second drain electrode; a third semiconductor chip disposed over the top surface of the third die pad, the third semiconductor chip including a first driver circuit for driving the high side MOSFET and a second driver circuit for driving the low side MOSFET; a resin body covering the first, second, and third semiconductor chips, the resin body having a pair of first side surfaces opposite each other, a pair of second side surfaces opposite each other, and a top surface and a bottom surface opposite each other, the top and bottom surfaces intersecting the first and second pairs of side surfaces, the bottom surfaces of the first, second and third die pads being exposed from the bottom surface of the resin body, a first metal plate coupled to the first source electrode pad of the first semiconductor chip and the second die pad; and a second metal plate having a top surface and a bottom surface opposite each other and coupled to the second source electrode pad of the second semiconductor chip and the fourth leads, the bottom surface of the second metal plate facing toward the second semiconductor chip, wherein the second metal plate has an opening which penetrates the second metal plate from the top surface to the bottom surface thereof.