A fully decoupled LC tank VCO based 16 to 19 GHz PLL in 130nm SiGe BiCMOS achieving −131dBc/Hz phase noise at 10MHz offset

This paper describes a technique for reducing oscillator phase noise through a circuit topology that decouples the LC tank from the active devices, achieving a higher amplitude of oscillation not limited by the active device breakdown voltage. This fully decoupled LC tank topology also reduces noise injection into the tank, which, coupled with the higher tank swing, results in low phase noise operation. As proof of concept, a VCO operating at 16 to 19 GHz is implemented in the IBM 130nm SiGe BiCMOS technology f _T /f _max of 200/280 GHz). The VCO achieves a phase noise of -131dBc/Hz at a 10MHz offset from the carrier.