一种输入输出轨到轨CMOS运算放大器的设计

随着电源电压的日益降低,信号幅度不断减小,在噪声保持不变的情况下,信噪比也会相应地减小。为了在低电源电压下获得高的信噪比,需提高信号幅度,而输入输出轨到轨运算放大器可获得与电源电压轨相当的信号幅度。中文在理论分析了输入输出轨到轨CMOS运算放大器主要架构优缺点后,给出了一种新的输入输出轨到轨CMOS运算放大器的设计,该电路在华润上华0.18 μm工艺平台上流片验证。测试结果表明,输入范围从0到电源电压,输出范围从50 mV到电源电压减去50 mV,实现了输入输出轨到轨的目标。

An Input Output Rail-to-rail CMOS Operational Amplifier Design

With the power supply decreases gradually,the amplitude of the signals reduce at the same time.However the noise level retains which leads to the signal-to-noise ratio (SNR) being worse.To get higher SNR under lower power supply,the amplitude of signals should be enhanced.Input and output rail-to-rail operational amplifiers can get amplitude near to power supply rails.Firstly theoretical analysis of advantage and shortcomings of input output rail-to-rail CMOS operational amplifier main structure is developed,then the paper presents a new design of an input and output rail-to-rail operational amplifier.The circuit was taped out and verified on CSMC's 0.18 μm process.Test results show that the input range could be from 0 to power supply and the output range could be from 50mV to power supply minus 50mV,which achieves the target of input's and output's rail-to-rail.