A CMOS QVCO using combined capacitor-coupling, bottom-series coupling and splitting switched biasing techniques

Abstract

A quadrature voltage-controlled-oscillator (QVCO) is presented and fabricated in standard 0.18µm RF CMOS technology. Passively Capacitor coupling, actively bottom-series (BS) coupling and splitting switching biasing (SSB) techniques are combined and employed for the QVCO to improve its phase noise performance without loss of the voltage headroom. Measured results show the proposed QVCO achieves a tuning range from 0.88 to 1.04 GHz, phase noise of -71.2dBc/Hz@1kHz and -113.1dBc/Hz@1MHz, and a phase-noise figure-of-merit (FOM_T) of 189.7 dBc/Hz from a offset frequency of 1kHz , with an occupied die area of 1283µm×715µm and power consumption of 11mW from a 1.8V voltage supply.