780/868/915MHz频段无线传感器网络低功耗电流复用频率综合器

780/868/915 MHz frequency bands low power current reusing frequency synthesizer for wireless sensor network

提出了一种适用于780(中国)/868(欧洲)/915(美国)MHz频段无线传感器网络收发机的低功耗频率综合器,采用电流复用技术使压控振荡器(VCO)和分频器共享偏置电流从而降低了功耗.集成了新型锁定检测门限可编程的锁定检测器用于锁相时间指示.频率综合器采用0.18μm CMOS工艺进行验证和测试.测试结果显示:频率覆盖范围约为770～930 MHz;输出信号频率为868 MHz时带内相位噪声为-87 dBc/Hz,频偏100 kHz和1 MHz处相位噪声分别为-98和-124 dBc/Hz;在不同锁定检测门限下测得锁定时间为91～112μs;在工作电压为1.8 V时,频率综合器工作电流约为3.9 mA.

A low power frequency synthesizer suited for wireless sensor network transceiver in 780（China）/868（Europe）/915（USA）MHz frequency bands is proposed.The current reusing technique is adopted to make the voltage controlled oscillator（VCO）and divider share a common bias current so to cut down the power budget.A novel lock detector with programmable locked-detecting thresholds is integrated in frequency synthesizer to detect the locked time.Frequency synthesizer was fabricated in 0.18 μm CMOS（complementary metal oxide semiconductor） technology and the measurement was carried out.Test results show that the frequency rang of synthesizer is 770-930 MHz;when the output frequency is 868MHz,the phase noise is-87dBc/Hz in band,with-98dBc/Hz@100 kHz and-124dBc/Hz@1MHz;the measured locked time is 91~112 μs with different locked-detecting thresholds;the total current of synthesizer is 3.9 mA under 1.8 V supply.