高速运算放大器低失调输入级的设计  

Design of Low Offset Input Level of High Speed Operational Amplifier

作　　者：石宁 李逸玚 沈坚 任罗伟 SHI Ning;LI Yiyang;SHEN Jian;REN Luowei(Wuxi I-Core Electronics Co.,Ltd,Wuxi 214072,China)

机构地区：[1]无锡中微爱芯电子有限公司,江苏无锡214072

出　　处：《电子与封装》2023年第5期34-39,共6页Electronics & Packaging

摘　　要：差分对结构是运算放大器(运放)的基础结构,对电路性能至关重要。现实中,工艺偏差无法避免,其带来的失配会影响运放的精度。对多级运放而言,输入级的失调程度决定了整个放大器的精度,因此低失调输入级成为运放设计的重点之一。为获得低失调的运放输入级,研究了差分对电阻RC和电路失配的关系,通过修调失配电阻ΔRC补偿其余失配项带来的影响。使用西岳4μm 50 V的工艺做全芯片参数验证,结果表明,失调电压低于60μV,相较于通用运放减小了76%;温漂系数可达0.3μV/℃,相较于通用运放减小了50%。这种方法简单、方便,可避免对电路结构做大规模调整,且对电路功耗的影响可以忽略。Differential pair structure,as the basic structure of operational amplifiers,is critical to circuit performance.In reality,the process deviations cannot be avoided,and the mismatch they bring will affect the accuracy of the operational amplifier.For multi-stage operational amplifiers,the degree of detuning of the input stage determines the accuracy of the whole amplifier,so the low offset input level has become one of the key points of operational amplifier design.In order to get a low offset operational amplifier input stage,the relationship between differential pair resistor RC and circuit mismatch is studied,and the effect of the remaining mismatch term is compensated by trimming the mismatch resistorΔRC.The overall chip parameters verification is realized in the process XY 4μm 50 V.The result shows that the offset voltage is below 60μV,which is 76%less than the general operating amplifiers.The temperature drift coefficient can reach 0.3μV/℃,which is 50%less than the general operating amplifiers.This method is simple and convenient,avoids large-scale adjustments in the circuit structure,the impact on circuit power consumption can be ignored.

关 键 词：模拟集成电路 双极型运算放大器 差分放大器 高精度 低失调 

分 类 号：TN431.1[电子电信—微电子学与固体电子学]