A Wideband, Low-Noise, and High-Resolution Digitally-Controlled Oscillator for SDR Applications

An integrated wide tuning range, low phase noise and high frequency resolution digitally controlled oscillator (DCO) in 90 nm CMOS technology for software-defined radio (SDR) frequency synthesizers is presented. The switched-capacitor equipped with fine frequency resolution and tail noise filtering techniques are adopted to achieve a wide frequency range from 8.14-11.90 GHz with power consumption varying from 9.4-24.5 mA under 1-V supply. The measured phase noise is -108.4 to -115.4 dBc/Hz at 1-MHz offset. Furthermore, a design technique what we term as C_eq-C_tunε diagram and the methodology for designing wide tuning range and low phase noise oscillator in single core are also presented.