A novel high-speed CMOS fully-differentical ring VCO

Based on a standard 0.18μm CMOS technology, a novel four-stage fully-differential ring voltage-controlled oscillator (VCO) with high speed, low power and a wide tuning range is proposed. The inductive shunt peaking technique with active inductors is employed to expand the bandwidth of the delay cell, and a pair of PMOS transistors with gates connected to the ground is added to to increase the oscillation frequency and improve the linearity of the VCO. Simulation results show that, from a supply voltage of 1.8V, a tuning range of 4.9~5.9 GHz, a phase noise of -86.7dBc/Hz@1MHz, and a FOM of -149.7 at a oscillating frequency of 5.4 GHz are achieved. Only a power of 8.1mW is consumed.