Patent ID: 8295057

Claim:
A semiconductor device including an RF power amplifier circuit, comprising: (a) a semiconductor chip including: an input stage transistor of the RF power amplifier circuit having a first input node and a first output node, an output stage transistor of the RF power amplifier circuit having a second input node and a second output node, the first output node being electrically coupled to the second input node; and (b) a mounting substrate over which the semiconductor chip is mounted, the mounting substrate having a main surface and a back surface opposite each other, comprising: a plurality of external terminals disposed over the back surface; a conductive plate formed over the main surface of the mounting substrate; and a through-hole wire formed right below the conductive plate in the mounting substrate, wherein the semiconductor chip is disposed over the conductive plate, one of the external terminals is electrically coupled to the first and second input nodes, another one of the external terminals is electrically coupled to the first and second output nodes, the plurality of external terminals includes a reference-potential external terminal, and the conductive plate and the reference-potential external terminal are electrically coupled via the through-hole wire.