摘要
硅基MEMS振荡器的频率温度系数高达-30 ppm/℃,是石英晶体振荡器的100倍以上,因此必须进行频率温度补偿。静电反馈是一种低功耗补偿技术,但是静电力小,对于频率较高的振荡器效果不理想。设计了一种具有高Q值的I2BAR结构的高频振荡器,通过优化振荡结构、制作纳米尺度间隙、采用高掺杂衬底来提高静电反馈的作用。建立了器件的机电耦合解析模型,并根据器件的物理结构和尺寸建立了包含寄生效应的等效电学模型,进行PSpice仿真。实验测得振荡器在30 Pa气压下具有48 000的Q值,当电压从1 V增加到25 V,频率变化-1 194 ppm,频率温度特性为-14 ppm/℃,表明通过静电反馈能够补偿85℃范围内温度变化引起的频率偏移。
The TCF（Temperature Coefficient of Frequency） of MEMS oscillator is-30 ppm/℃, which is 100 times than quartz crystal oscillator, the frequency must be compensated. Tuning by static electricity is a low power compensation technology,but it＇s too small to compensate high frequency oscillator. An I^2BAR based oscillator with high Q value is designed, by optimizing the resonant structure, making nanometer gap and using highly doped substrate to increase the effect of electrostatic. An analytical relationship between resonant frequency and static electricity is carried out, then establish an equivalent electrical model and simulate with PSpice. The experiment shows that the oscillator has a Q value of 48000 at 30 Pa pressure, when increase the voltage from 1V to 25 V, frequency changes-1195 ppm, and the TCF is-14ppm/℃, shows electrostatic tuning can compensate frequency shift caused by temperature within the range of 85℃.
出处
《电子设计工程》
2016年第21期156-159,共4页
Electronic Design Engineering
基金
国家863计划项目(2013AA041106)
上海市科委项目(13dz1100300)
关键词
MEMS振荡器
静电反馈
电学模型
温度补偿
MEMS oscillator
electrostatic tuning
electrical model
temperature compensate
