Title :
Analysis on resonator coupling and its application to CMOS quadrature VCO at 8 GHz
Author :
Baek, Donghyun ; Song, Taeksang ; Ko, Sangsoo ; Yoon, Euisik ; Hong, Songcheol
Author_Institution :
Dept. EECS, Korea Adv. Inst. of Sci. & Technol., Daejeon, South Korea
Abstract :
A low phase noise CMOS quadrature VCO is presented. A transformer resonator coupling is analyzed. It is found that the coupled resonator has high frequency selectivity. The Q factor of a coupled resonator is (1+k) times higher than a single LC resonator. This enhancement leads to low phase noise and low power consumption of a VCO. The VCO is implemented using 0.18 μm CMOS technology. Two VCOs are linked to generate I-Q signals by the direct current modulation method. The VCO shows low phase noise performances of -110 and -117 dBc/Hz at the offset frequencies of 600 kHz and 1 MHz respectively. The oscillation frequency is 8 GHz. The tuning range of 250 MHz is achieved with a control voltage from 0 to 1 V. The VCO draws 8 mA in core circuits with 3 V supply.
Keywords :
CMOS integrated circuits; Q-factor; circuit tuning; coupled circuits; integrated circuit design; integrated circuit measurement; integrated circuit noise; phase noise; resonators; voltage-controlled oscillators; 0 to 1 V; 0.18 micron; 3 V; 8 GHz; 8 mA; I-Q signals; Q factor; control voltage; core circuits; coupled resonator frequency selectivity; direct current modulation method; low phase noise CMOS quadrature VCO; offset frequencies; oscillation frequency; power consumption; resonator coupling; single LC resonator; transformer resonator coupling; tuning range; CMOS technology; Circuit optimization; DC generators; Energy consumption; Phase noise; Q factor; Resonant frequency; Signal generators; Voltage control; Voltage-controlled oscillators;
Conference_Titel :
Radio Frequency Integrated Circuits (RFIC) Symposium, 2003 IEEE
Print_ISBN :
0-7803-7694-3
DOI :
10.1109/RFIC.2003.1213899
