Patent ID: 7336136

Claim:
A high frequency semiconductor circuit device comprising: a transmission oscillator which outputs differential signals, the differential signals including a first differential signal and a second differential signal; a first external terminal for outputting the first differential signal generated at the transmission oscillator; a phase detection circuit which compares the phase of a reference signal with the phase of a feedback signal and controls said transmission oscillator according to phase difference of these signals; a second external terminal for receiving externally supplied signals; a first mixer circuit which combines a signal inputted to the second external terminal with a signal of a predetermined frequency; and an equivalent impedance circuit having an impedance equivalent to the impedance between one output terminal of said transmission oscillator and said first external terminal, wherein one output terminal of said transmission oscillator of differential output configuration and said first external terminal are connected by a first bonding wire, and the other output terminal of said transmission oscillator and one terminal of said equivalent impedance circuit are connected by a second bonding wire, so that said first differential signal is outputted to external of the high frequency semiconductor circuit device via said first external terminal and said second differential signal is provided to the equivalent impedance circuit.