A Fast Startup Crystal Oscillator with Digital SAR-AFC Based Two-Step Injection  

作　　者：Bo ZHOU Yifan LI Zuhang WANG 

机构地区：[1]School of Integrated Circuits and Electronics,Beijing Institute of Technology,Beijing 100081,China

出　　处：《Chinese Journal of Electronics》2024年第5期1147-1153,共7页电子学报（英文版）

基　　金：supported by the Beijing Natural Science Foundation(Grant No.4222076).

摘　　要：Crystal oscillators(XOs)provide a high-precision reference frequency but have a long startup time,which severely increases the average power consumption in duty-cycled systems.This paper proposes a fully-digital low-cost two-step injection technique,by using a successive approximation register(SAR)based auto frequency control(AFC)loop,to speed up the startup behavior of XOs.A theoretical analysis is carried out to determine the optimum injection time and design low-power XOs.Fabricated in a 65 nm CMOS process,the proposed 12 MHz fast startup XO occupies an active area of 0.02 mm^(2) and achieves a startup time less than 35μs.The XO power consumption in the steady state is 40μW from a 1.0-V supply,with a startup energy of 17.2 nJ.

关 键 词：Crystal oscillator Two-step injection Successive approximation register Auto frequency control Fully-digital Fast startup 

分 类 号：TN752[电子电信—电路与系统]