This letter presents a wide frequency tuning range (FTR), faulttolerant, and common-mode-noise (CMN)-suppressed LC-VCO using the Reversed-varactor (RV) technique. The RV technique maintains a wide frequency tuning range, ensures that the CMN emitted from the internal devices and external working environment is not multiplied by K VCO 2 , and improves the fault-tolerant property of the LC-VCO. The simulation results show that this technique reduces the phase noise (PN) by 6d Bc/Hz to 6.8 dBc/Hz, while the frequency fluctuation due to the single-event-transient (SET) effect decreases by about 90.2%. The proposed LC-VCO works from 14.6 GHz to 21.3 GHz, has -100.3 dBc/Hz@1 MHz at 18.2 GHz working frequency and 5.7 mW power consumption.