Title :
A Low-phase-noise 1-GHz LC VCO Differentially Tuned by Switched Step Capacitors
Author :
Tang, Zhangwen ; He, Jie ; Min, Hao
Author_Institution :
ASIC & Syst. State Key Lab., Fudan Univ., Shanghai
Abstract :
This paper proposes a novel 1-GHz LC oscillator differentially tuned by switched step capacitors, which is implemented in a 0.25mum 1P5M CMOS process. A period calculation technique (PCT) is adopted to analyze the differential tuning characteristic of switched step capacitors. Due to the symmetric oscillation waveforms, the differentially tuned LC VCO has 7 dB phase noise reduction in the 1/f 3 region compared to the single-ended tuned topology, and 23.6dB CMRR. It achieves phase noise -83 dBc/Hz, -107 dBc/Hz and -130 dBc/Hz respectively at 10-kHz, 100-kHz and 1-MHz offsets, while dissipating 3.3 mA current at 2.6 V power supply. Chip size is 0.82 mm times 0.84 mm
Keywords :
1/f noise; CMOS integrated circuits; UHF oscillators; circuit tuning; phase noise; switched capacitor networks; voltage-controlled oscillators; 0.25 micron; 0.82 mm; 0.84 mm; 1 GHz; 1/f3 region; 2.6 V; 3.3 mA; CMOS process; LC oscillator; differential tuning characteristic; low-phase-noise LC VCO; period calculation technique; phase noise reduction; single-ended tuned topology; switched step capacitors; symmetric oscillation waveforms; 1f noise; Capacitors; Circuit noise; Circuit optimization; Low-frequency noise; Phase noise; Tuning; Varactors; Voltage; Voltage-controlled oscillators;
Conference_Titel :
Asian Solid-State Circuits Conference, 2005
Conference_Location :
Hsinchu
Print_ISBN :
0-7803-9162-4
Electronic_ISBN :
0-7803-9163-2
DOI :
10.1109/ASSCC.2005.251752
