Patent ID: 7817437

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