一种新型单端输入双端输出LNA设计

论文总字数：25830字

摘 要

近些年来，超再生接收机因其独特的优点，得到了广泛的研究和发展。超再生接收机与其他种类的接收机相比，有着如下显著的优点：低功耗——超再生振荡器受熄灭信号控制，振荡过程有一定的占空比，与一直处于振荡状态下的超外差接收机相比，可以明显降低系统功耗；低成本——超再生接收机的系统结构简单，元器件少且成本低，并且可以进一步降低功耗；灵敏度比较高——超再生接收机的灵敏度比超外差接收机更高。

本文就是为超再生接收机设计一款可以工作在433MHz的单端输入、双端输出的低噪声放大器（LNA），将低噪声放大器和Balun和并起来。Balun-LNA 不需要附加的巴伦，降低了系统的复杂性和功耗。电路结构中无电感设计，能够很好地减少芯片的面积，从而降低成本。

本文采用0.35um CMOS工艺设计。整个设计都是在 Cadence 软件环境下进行的，包括电路仿真和版图设计。仿真最终结果表明：S11 小于 -10 dB ，S21 、 S31可以达到8 dB ，且两者相差不超过1 dB , 相位满足180^o 5^o ,NF小于4 dB 。

关键词：CMOS管，共源共栅，电流镜，低噪声放大器，S参数，噪声系数，线性度

DESIGN OF A SINGLE-ENDED INPUT DOUBLE-ENDED OUTPUT LNA

Abstract

Recenrt years, due to its special advantages, Super-Regenerative Receiver is researched and developed widely. Compared with other kinds of receives, it has the following advantages : 1 . Low power consumption — the Super-Regenerative oscillator is controlled by quench signal . There is a certain oscillation duty ratio, which makes the lower power consumption than the Super-Heterodyne receiver. 2. Low cost—the Structure of Super-Regenerative Receiver is simple and it needs fewer components. 3. Higher sensitivity—it has a better performance in sensitivity comparing to the Super-Heterodyne receiver.

In this paper, a LNA for Super-Regenerative Receiver is designed, which has one input and two outputs. It works at the frequency of 433M and it combines the LNA with Balun . Contrast to the conventional single-ended output LNA, the additional Balun is not needed in Balun-LNA, which reduces the complexity and power dissipation of the system. Moreover , this kind of inductorless topology significantly saves the area and cost of chip.

Using SMIC 0.35 μm CMOS process , the circuit simulation and layout design of L NA is done under the Cadence software environment , including the circuit simulation and layout design . The result shows that S11 is less than -10dB. S21、S31 can reach 8dB and the short of them is under 1dB. NF is less than 4dB . These post-simulation results of the LNA can meet the requirements of the design specifications.

Keywords: CMOS , Cascode , Current mirror , LNA , S-Parameter , Noise Figure , Linearity

目录

摘要 …………………………………………………………………………………………………………Ⅰ

Abstract ……………………………………………………………………………………………………Ⅱ

第一章 绪论 ………………………………………………………………………………………………4

1.1选题背景和意义 …………………………………………………………………………………4

1.2设计难点 ………………………………………………………………………………………7

第二章 电路分析及仿真 ……………………………………………………………………………8

2.1 原理分析 ………………………………………………………………………………………8

2.1.1 场效应管 …………………………………………………………………………………8

2.1.2 共源放大器 ……………………………………………………………………………12

2.1.3 共栅放大器 ……………………………………………………………………………13

2.1.4 镜像电流源 ………………………………………………………………………14

2.1.5 共源共栅结构（Cascode） …………………………………………………16

2.1.6 原理图 …………………………………………………………………………………18

2.2 LNA电路噪声来源和噪声系数 ………………………………………………………19

2.2.1 引言 ……………………………………………………………………………19

2.2.2 起伏噪声的来源 ………………………………………………………………21

2.2.3 噪声系数 ……………………………………………………………………………23

2.2.4 NF仿真 ……………………………………………………………………………26

2.3 S参数 ……………………………………………………………………………27

2.3.1二端口S参数理论 ………………………………………………………27

2.3.2 S参数仿真 ……………………………………………………………………………28

2.4 线性度 ……………………………………………………………………………31

第三章 版图设计 ………………………………………………………………………………………35

3.1 版图设计规则 ………………………………………………………………………35

3.1.1最小宽度 ………………………………………………………………………35

3.1.2最小间距 ………………………………………………………………………36

3.1.3最小交叠 ………………………………………………………………………37

3.2版图设计注意事项 ……………………………………………………………………37

3.2.1寄生效应 ………………………………………………………………………37

3.2.2匹配与对称 ……………………………………………………………………39

3.2.3保护环 ……………………………………………………………………40

3.2.4其他注意点 ……………………………………………………………………41

3.3绘制版图 ……………………………………………………………………41

结论 ………………………………………………………………………………………………………45

致谢 ………………………………………………………………………………………………………46

参考文献（References） …………………………………………………………………………45

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