一种工作于亚阈值区的低功耗CMOS晶体振荡器

A Low-Power Subthreshold CMOS Crystal Oscillator

提出了一种基于亚阈值区的低功耗CMOS晶体振荡器电路。通过环路增益和相位的分析,得出了一般晶体振荡电路的振荡性能优化条件;并通过亚阈值电流源、亚阈值MOS管反馈、电流源放大缓冲级以及电路的其他改进,进一步优化振荡电路的性能。根据这种设计,采用SMIC0.18μm CMOS单层多晶硅六层金属工艺,实现了一个功耗电流0.7μA的CMOS晶体振荡器。

A low-power crystal oscillator with subthreshold MOS transistors was presented. Based on the analysis of the loop gain and phase, optimized conditions for improvement of conventional oscillator circuits were obtained. And improvements were also made on the subthreshold current source, feedback of the subthreshold MOS transistors, amplifier buffer of the current source and other circuit design, to further optimize the oscillator circuit. Based on the proposed design, a crystal oscillator with 0. 7 μA of power was implemented using SMIC＇s 0, 18 μm CMOS single-poly six-metal process.