新型超高速运算放大器低失调型输入级

A New Input Stage With Low-Offset Suitable for Very High-Speed Operatlonal Amplifiers

对于超高速集成运算放大器，如无特殊措施，无论是场效应型还是双极型超高速运放，原则上均不能同时获得低的失调电压和低的失调电流。各种旨在降低电路失调而对输入级所作的改进，大部分是针对双极型高速运放。但是这些改进措施要不是增大了工艺难度，就是改善了一个失调参数的同时又恶化了另一个失调参数。我们在分析了各种高速运放输入级输入失调的基础上，设计了一种新的低失调型双极输入级电路。理论分析及计算机电路模拟证实这种输入级电路的失调低于目前所见到的各种形式的输入级，且不增加工艺难度，是一种比较理想的高精度超高速集成运放输入级。

For very high-speed/high-speed op amp IC's,whether it is field-effect type or bipolar type,it is generally not possible to achieve low offset voltage and low offset current at the same time without special measures.Of various modifications on input stage to lower offset of a circuit,most are aiming at bipolar high-speed op-amps.These modification measures,however,either com-plicate the process,or improving one offset parameter while deteriorating another.Based on the analysis of input offset in different high-speed/very high-speed op-amps'input stages,a new bipo-lar input stage with low offset is designed.Theoretical analysis and circuit computer simulation show that offset of the new input stage is lower than various types of input stages and the process is not complicated.It is,therefore,an ideal input stage for high-accuracy and very high-speed op-amp IC's