双通道零漂移精密集成运算放大器设计

Design of dual-channel zero-drift precision integrated operational amplifier

设计了一种双通道、零漂移、高精密的轨对轨运算放大器,该运算放大器结合了自动调零技术与乒乓架构,对信号进行连续处理的同时也避免了互调失真的产生。整体电路结构主要包括:主运算放大器、调零运算放大器、频率补偿电路、开关电路、振荡器、非交叠时钟电路以及基准电路。其中,基准电路、振荡器,非交叠时钟电路为共用模块,其余部分在双通道中独立工作。基于Cadence软件,采用国内0.6μm BCD工艺进行仿真设计,结果表明,在5 V的电源电压条件下,实现的性能指标为:输入失调电压<3.6μV,失调电压漂移<0.007μV/℃,开环增益>125 dB,共模抑制比>135 dB,电源抑制比>117 dB,增益带宽积>1.46 MHz,同时能够实现轨对轨输入输出。

A dual-channel,zero-drift,high-precision rail-to-rail operational amplifier is designed,which combines auto-zero technology with ping-pong architecture to continuously process signals while avoiding intermodulation distortion.The overall circuit structure mainly includes:main operational amplifier,zero-switching operational amplifier,frequency compensation circuit,switching circuit,oscillator,non-overlapping clock circuit and reference circuit.In the structure research,the reference circuit,oscillator,and non-overlapping clock circuit are common modules,and the rest work independently in dual channels.Based on Cadence software,the domestic 0.6μm BCD process is used for simulation design,and the results show that under the condition of 5 V supply voltage,the achieved performance indicators are:input offset voltage<3.6μV,offset voltage drift<0.007μV/℃,open-loop gain>125 dB,common-mode rejection ratio>135 dB,power supply rejection ratio>117 dB,gain bandwidth product>1.46 MHz,and rail-to-rail input and output can be realized.