A Novel LC VCO with High Output Power and Low Phase Noise Using Differential Active Inductor

Abstract

This paper presents a novel LC voltage-controlled-oscillator (VCO) based on active inductor (AI). Taking advantage of equivalent RLC model of the AI, a novel tunable differential AI (DAI) is designed and used to act as the LC tank of the VCO. First, a tunable DAI with cascode-structure and current-mirror feedback networks is designed to achieve high quality factor $(\pmb{Q})$ and high equivalent parallel resistance (Rp). Then, the DAI is used to replace LC in VCO to realize good comprehensive performance of VCO such as low phase noise, low power consumption and high output power. Based on TSMC $\mathbf{0.18}\mu\mathbf{m}$ RF CMOS process, the novel VCO is verified by Agilent's Advanced Design System (ADS). The results show that under the supply voltage of 1.8V, the output power reaches up to −4.2 dBm, a frequency tuning range is in 1.126-2.713 GHz, and the phase noise at 1-MHz offset is −117.2 dBc/Hz. A power of only 13.6 mW is consumed.