Patent ID: 7061329

Claim:
A semiconductor device comprising: an input-side matching circuit having paired first and second input-side circuits; an output-side matching circuit having paired first and second output-side circuits; first and second transistors for amplification, wherein the first transistor is connected between the first input-side circuit of the input-side matching circuit and the first output-side circuit of the output-side matching circuit and the second transistor is connected between the second input-side circuit of the input-side matching circuit and the second output-side circuit of the output-side matching circuit; a first balanced circuit connected to the input-side matching circuit and respectively supplying to the first and second input-side circuits of the input-side matching circuit two signals different in phase by 180 degrees; and a second balanced circuit connected to the output-side matching circuit, and respectively receiving from the first and second output-side circuits of the output-side matching circuit two signals different in phase by 180 degrees, wherein at least one of the first and second balanced circuits includes a first inductor, a second inductor, and a capacitor connected between the first inductors and the second inductor, the capacitor being connected to a virtual grounding node.