一种输入输出轨到轨的电流模式仪表放大器设计

摘要

A current-mode instrumentation amplifier (CMIA) based on standard CMOS process is presented. The chopper pair used in the CMIA is for removing offset and I/f noise. Moreover, associated with positive and negative charge pump the CMIA have true Rail-to-Rail input range. A prototype chip is designed and fabricated by using TSMC's 0.25μm CMOS mixed-signal process. The system gain is determined by using two off-chip resistors. The measurement results show that the proposed CMIA with 60 kHz chopper and system gain of 40dB, have common-mode rejection ratio of 100dB, input-referred dc offset of-35μV, input-referred noise of 9nV/√Hz and input common mode range from -0.1V to 3.5V under the condition of 3V supply.%本文提出了一种基于标准CMOS工艺的电流模式仪表放大器.该放大器内部运放采用斩波调制技术去除低频1/f噪声和失调,并采用正、负电荷泵,使系统具有轨到轨的输入能力.芯片使用TSMC 0.25μm CMOS混合信号工艺模型设计并流片.测试结果表明,使用60kHz的斩波频率,系统增益为40dB时,具有100dB的共模抑制比和-35μV的失调电压,以及9nV/√Hz的输入相关噪声.仪表放大器使用3V单电源供电,系统增益用两个片外电阻确定,共模输入电压范围从-0.1V到3.5V.