A Low Phase Noise Low Power Wide Tuning-Range VCO Using Transistor-Based Active Inductor

A high performance voltage-controlled-oscillator (VCO) using novel transistor-based active inductors (AIs) is presented. The designed AI, featured with wide operation bandwidth, tunable inductance and high quality factor (Q), is connected in parallel with a voltage-controlled array capacitor (VCAC) to form LC resonant tank, resulting in lower phase noise and wider frequency tuning range of VCO. The performances of the VCO are further improved by combining a current-reused cross-coupling pair (CR-CCP) to realize low power consumption and a tail current source noise reduction module (TCS-NRM) to reduce phase noise. As a result, the VCO with high Figure of Merit (FOM) is achieved. Based on TSMC 0.18-μm CMOS process, the proposed VCO is verified by Cadence Design Systems. The results show that the oscillation frequency can be tuned from 6.0 GHz to 8.4 GHz, the lowest phase noise is -111.6 dBc/Hz at 1-MHz offset, and the power consumption is 1.68 mW, and hence the FOM reaches -186.1 dBc/Hz.