微机械(MEMS)圆盘谐振器的振荡器具有相位噪声低,抖动小,温漂小等特点.采用TSMC0.18μmCMOS工艺设计实现了一款用于驱动MEMS圆盘谐振器的高增益、低噪声和低功耗跨阻放大器.该放大器采用低功耗宽带电流预放大和电流电压转换级输入技术,结合基于Cherry-Hooper反相器电压放大的电路结构,实现了增益、带宽、噪声、低电源电压和动态范围等指标间的折衷,成功驱动了MEMS圆盘谐振器.Spectre仿真表明,单端跨阻增益高达115dBΩ,-3dB带宽超过500MHz,等效输入噪声电流平均值为25pA/槡Hz,功耗仅为17.6mW,芯片面积(包括所有PAD)为620μm×620μm.
Disc-Like MEMS oscillators are compared with quartz crystal oscillator counter parts in terms of phasenoise,jitter, and temperature stability. Base on these characteristics, a high gain, low noise and low power transimpedanee amplifier is proposed to implement and driver a Disc-Like MEMS oscillator using TSMC 0. 18 μm CMOS technology. Aiming at Disc-Like MEMS oscillators having a parasitic capacitance of 0. 5 pF, a low power broadband current pre-amplifier combined with a current-to-voltage conversion stage and an inverter based wideband Cherry-Hooper amplifier are used to realize the good tradeoff between gain, bandwidth, noise, lower power voltage and dynamic range. Spectre simulation indicate:the single-end transimpedance gain is 115 dBΩ, the 3 dB bandwidth is beyond 500 MHz, the average input equivalent noise current is 25 pA√Hz , and the power dissipation is only 17. 6 mW,The die size (including all the PADs) is as small as 620 μm×620 μm.