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. †

A novel four‐stage fully differential ring voltage controlled oscillator (VCO) is presented and implemented in 0.18 μm CMOS technology. The fully differential delay cell is chosen over the pseudo‐differential one to avoid the cross‐coupling pair, increase the oscillation frequency and improve common‐noise suppression. The inductive shunt peaking technique with active inductors instead of its passive counterpart is used to expand the bandwidth of the delay cell and then increase the oscillation frequency of the VCO without the expense of excessive area. The current bleeding transistor pair is connected in shunt with the tuning transistor pair in order to make sure the VCO oscillate over the entire tuning voltage with proper phase noise. Measurement results show that, from a single voltage supply of 1.8 V and an occupied area of 475 μm × 275 μm, the proposed VCO achieves an oscillation frequency range from 3.25 to 4.2 GHz with the optimum phase noise of −92.28 dBc/Hz at 1 MHz and an optimum FOM of −154.80 dBc/Hz.

A high-performance inductorless ring VCO with wide tuning range and extended monotonic tuning voltage range (MTVR) is proposed and fabricated in standard 0.18 µm CMOS technology. By combining the crossing-strength-tuning and load-resistance-tuning techniques with opposite tuning characteristics, the MTVR for the proposed VCO can be widened significantly. The dual-delay path technique is employed to improve the oscillating frequency. The cross-coupled pair is added to reduce phase noise and guarantee reliable differential-mode oscillation over the wide tuning voltage range. With an occupied area of 475 µm × 275 µm and a single supply voltage of 1.8 V, measurement results show the proposed VCO can oscillate with a frequency range from 1.57 to 2.76 GHz, phase noise of −91.12 dBc/Hz @ 1 MHz and FOM T of 164.5 dBc/Hz @ 1 MHz and extended MTVR.