A fast lock frequency synthesizer using an improved adaptive frequency calibration

• Published in: Journal of semiconductors Vol. 31; no. 6; pp. 131 - 136
• Main Author: 阴亚东 阎跃鹏 梁伟伟 杜占坤
• Format: Journal Article
• Language: Chinese; English
• Published: IOP Publishing 01.06.2010
• Subjects: CMOS; 加载频率; 电压控制振荡器; 自适应; 锁定时间; 频率合成器; 频率校准; 频率检测器
• ISSN: 1674-4926
• DOI: 10.1088/1674-4926/31/6/065011

An improved adaptive frequency calibration（AFC） has been employed to implement a fast lock phaselocked loop based frequency synthesizer in a 0.18μm CMOS process.The AFC can work in two modes：the frequency calibration mode and the store/load mode.In the frequency calibration mode,a novel frequency-detector is used to reduce the frequency calibration time to 16 us typically.In the store/load mode,the AFC makes the voltage-controlled oscillator（VCO） return to the calibrated frequency in about 1μs by loading the calibration result stored after the frequency calibration.The experimental results show that the VCO tuning frequency range is about 620-920 MHz and the in-band phase noise within the loop bandwidth of 10 kHz is-82 dBc/Hz.The lock time is about 20μs in frequency calibration mode and about 5 us in store/load mode.The synthesizer consumes 12 mA from a single 1.8 V supply voltage when steady.