用于MEMS惯性器件的低噪声读出电路设计

给出了一种用于MEMS惯性器件的低噪声读出电路设计,针对MEMS惯性器件大多采用电容量输出等特点,设计了一个低噪声运算放大器,利用该运放,设计了一种基于开关电容的电荷转移电路来将电容量转换为电压量,以便后续电路处理.采用了相关双采样(CDS)技术,较大地减少了电路和MEMS惯性器件的1/f噪声、热噪声,抑制了零漂.采用HHNEC 0.35 μmCMOS工艺制造,面积为1 mm×2 mm,与MEMS器件封装在一起,并进行了实际测试,结果表明,该读出电路基本满足要求,并具有较低的噪声.

Design of a Low-Noise Readout Circuit for MEMS Inertial Devices

A low-noise readout circuit was presented for MEMS inertial devices. A low-noise opamp was designed according to the characteristics of most MEMS inertial devices including capacitance output etc. And a charge transfer circuit based on switched-capacitors was designed to convert the capacitance to voltage for further processing. A correlated double sampling (CDS) technique was adopted to reduce the 1/f noise, thermal noise and suppress the zero-drift of the circuit and the MEMS inertial device. The chip designed measures 1 mm × 2 mm and was fabricated in HHNEC 0.35 μm CMOS process. The chip was packaged with the MEMS device together in one package. Experiments are taken to test the circuit, and the results show that it can satisfy the general specification required by the MEMS device with a lower noise.