Patent ID: 8035456

Claim:
A voltage-controlled oscillator (VCO), comprising: a cross-coupled transistors module, coupled to a first reference voltage; and a resonant module, coupled to the cross-coupled transistors module and a second reference voltage, the resonant module comprising: a first transistor, having a first source/drain terminal, a second source/drain terminal and a gate terminal, the first source/drain terminal coupled to the second reference voltage, the second source/drain terminal coupled to the cross-coupled transistors module and the gate terminal coupled to a bias voltage; a second transistor, having a first source/drain terminal, a second source/drain terminal and a gate terminal, the first source/drain terminal coupled to the second reference voltage, the second source/drain terminal coupled to the cross-coupled transistors module and the gate terminal coupled to the bias voltage; a first inductor and varactor string, coupled between the gate of the first transistor and a tuning voltage in serial; and a second inductor and varactor string, coupled between the gate of the second transistor and the tuning voltage in serial.