文档介绍：华中科技大学
硕士学位论文
低噪声CMOS运算放大器的研究与设计
姓名:詹昶
申请学位级别:硕士
专业:微电子学与固体电子学
指导教师:邹雪城
20070527
摘要
CMOS 运算放大器是模拟集成电路中最重要的模块之一。然而 MOS 晶体管会给
电路带来噪声,特别是随着 MOS 晶体管尺寸的减小和信号幅度的降低,电路的低频
噪声特性变得越来越重要。
本论文主要研究了各种经典结构运算放大器电路的噪声特性,以及降低噪声的方
法。并且研究了如何在运算放大器的噪声、功耗、电压余度和速度等性能参数之间进
行折衷。本文的研究角度是:首先从分析运算放大器电路中主要的噪声来源入手,然
后结合基本的噪声理论对电路中相应的元件参数进行设计,并且在运算放大器的各项
指标要求下再对某些元件的参数进行调整。
最后,本文以设计一个应用于 Sigma-Delta ADC 的调制器中的全差分运算放大器
为例子,先通过 Simulink 建模提取运放的参数,然后通过细致的手工计算得到选定结
构的运放的各个元件参数,接下来在参数验证的过程中对运算放大器的噪声特性进行
优化。其中,对闪烁噪声的降低是设计的重点。根据对所选用的运算放大器的闪烁噪
声谱密度表达式的分析,提出了通过建立多元函数求极值的方案,使得在尽可能小的
版图面积内使运算放大器的性能符合设计指标。
本文的研究基于“和舰 μm”的工艺,使用 HSpice 工具进行仿真,仿真结果显
示,研究设计基本获得成功。

关键词: 运算放大器,热噪声,闪烁噪声,谱密度,输入参考噪声电压
I
Abstract
CMOS Operational Amplifier (op-amp) is one of the most ponents in
analog integrated circuits. But the MOS transistors are “noisy”, moreover, as MOS device
sizes and signal levels are aggressively scaled down, the low frequency noise (LFN)
properties e increasingly important.
In this dissertation, the main research is about how to decrease the noise in op-amp
with classic topology and how to make tradeoff between noise and other characters such as
power and speed. It starts from seeking the dominating noise sources in op-amps, then
adjusts the parameters of ponents according to the primary theory of noise, and
makes tradeoff between noise and other characters.
The design of a full differencial op-amp, which is used in the modulator of a
Sigma-Delta ADC, is given as an example in the end. The parameters of the op-amp are
obtained by simulating in Simulink environment, and then they are transformed into actual
components artificially, the optimization of the noise character is carried out by validation
in the end. The decrease of flicker noise is studied as an emphasis of the design. A
multivariate function is created according to the expression of the spectrum density of the
1/f noise. Then both a satisfied design of the op-amp an