一种频率稳定的改进型CMOS环形振荡器

Improved CMOS ring oscillator with stable frequency

介绍了一种频率为1.2 MHz的CMOS环形振荡器的设计,工作电压范围是3 V^6 V,工作温度范围是-40℃~85℃。CMOS振荡器使用了Candence软件仿真工具设计,并采用无锡上华(CSMC)的标准0.5μm双多晶硅、三层金属CMOS工艺制作。为解决振荡频率随电压电源变化较大的问题,在分析传统的环形振荡器的基础上,提出了一种改进型的环形振荡器;然后使用Candence软件,在不同工艺角下,对电路进行仿真和分析,得到了电源电压和振荡频率的对应关系。研究结果表明,电源电压从3 V变化到6 V,振荡器输出频率最大变化范围为±5%。

1.2 MHz CMOS ring oscillator operates under voltage range 3 V～6 V and temperature range-40 ℃～85 ℃ was presented.This oscillator circuit was designed with Candence software,and was fabricated in the standard 0.5 μm double-poly,triple metal CMOS process of Wuxi CSMC.Aiming at the problem of oscillation frequency changes with the power supply voltage,a modified ring oscillator was presented,based on the analysis of the traditional ring oscillator.Then the corresponding relation of power supply voltage and oscillation frequency was received through circuit simulation and analysis by using Candence software.The results indicate that output frequency vary ±5% from the nominal frequency in the whole power supply voltage range 3 V～6 V.