A low-voltage low-phase-noise bottom-series LC QVCO using capacitor tapping technique

This paper presents a novel low-voltage low-phase-noise LC quadrature voltage controlled oscillator (QVCO) implemented in the TSMC 0.18-mum CMOS process. By using a combination of bottom-series coupling architecture and capacitor tapping technique, the QVCO achieves a zero resonator phase shift (RPS), a high loaded resonator quality factor, and limited phase noise contribution from the current source, all of which lead to a low phase noise. From a 5.3-GHz carrier, the measured phase noise is -123 dBc/Hz at 1-MHz offset with a 1.8-V power supply and -118 dBc/Hz at 1-MHz offset with a 1-V power supply.