静电防护中TVS对LNA阻抗网络影响的研究及应用

发布时间：2018-01-06 11:12

本文关键词：静电防护中TVS对LNA阻抗网络影响的研究及应用　出处：《南京师范大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着现代电子科技的迅猛发展,各种微电子和电路系统逐渐向高度集成化、微型化、低功耗方向发展.这在电路系统功能增强的同时,对电路和电子器件的电磁兼容(EMC)性也提出了越来越高的要求。而静电放电(ESD)是一种常见的电磁危害源。无线通信系统中,到达接收机的射频信号电平多为微伏数量级。因此,需要将微弱的信号进行放大。LNA低噪声放大器一般作为射频系统的第一级,极易受到来自外部的ESD冲击而损坏。瞬时浪涌电压抑制管(TVS)是有效的ESD电流抑制器件,在ESD电路的设计中和产品ESD问题的解决中扮演重要角色。TVS通常并在电路中泄放ESD电流以保护后面电路的正常工作。但在射频领域,TVS的寄生参数效应将大大增加,将影响LNA的输入阻抗,造成增益下降,无法正常工作。研究TVS对射频LNA匹配网络的影响具有较大的工程应用价值。针对上述问题,本文开展了“TVS引起的LNA阻抗网络失配的研究及应用”,包括以下四个部分：(1)对TVS,静电放电进行了简介。包括TVS特性,静电放电的电流特征,TVS在静电保护中的应用价值。(2)介绍了分析LNA阻抗网络的方法,S参数和阻抗圆。推导引出了LNA达到最大增益时的匹配条件,并对TVS引起的LNA阻抗失配进行了分析。(3)通过典型的LNA阻抗网络的设计,仿真,与实验,验证了TVS对LNA阻抗网络造成的额外负载效应。本文借助ADS (Advanced Design System)仿真软件,设计了一种典型的LNA晶体管电路,并以此为实验对象。本文拟通过对所需阻抗网络的计算分析,评估TVS对阻抗网络的负载作用,将仿真结果与实验结果进行对比。(4)设计两种工程应用方案,针对TVS引入的寄生参数进行抑制,使LNA能够有效地规避TVS的负面影响及ESD电流的冲击。理论分析与实验结果表明,TVS引入的负载与LNA阻抗网络处于同一数量级,会对LNA的正常工作造成不稳定的影响。在射频电路ESD问题的设计和解决中,使用TVS需要考虑TVS本身的寄生参数。本文给出的改善措施,虽然不能完全的恢复LNA的增益水平,但也能工程师在ESD保护电路设计时提供思路。研究TVS对射频匹配网络的影响具有较大的工程应用价值。
[Abstract]:With the rapid development of modern electronic technology, microelectronic circuit and system gradually to a high degree of integration, miniaturization, low power consumption direction. This increase in circuit system function at the same time, the electromagnetic compatible circuit and electronic device (EMC) is also put forward higher requirements. The electrostatic discharge (ESD) is a common electromagnetic hazard source in wireless communication system, reach the level of RF signals receiver for microvolt magnitude. Therefore, to weak signal amplification.LNA low noise amplifier in general as the first stage of the RF system vulnerable to external shocks and damage ESD. Instantaneous surge voltage suppression (TVS) is ESD current effective suppression devices play important role in.TVS and usually work in the circuit ESD discharge current to protect the back of the circuit in ESD to solve the problem of ESD circuit design and products. But In the RF field, effects of parasitic parameters of TVS will greatly increase, will affect the input impedance of the LNA, resulting in decreased gain, can not work normally. It has great application value to study effects of TVS on LNA RF matching network. Aiming at the above problems, this paper carried out the research and Application of LNA impedance mismatch caused by TVS network that includes the following four parts: (1) to TVS, electrostatic discharge are introduced. Including TVS characteristics, current characteristics of electrostatic discharge, the application value of TVS in electrostatic protection. (2) introduced the analysis method of LNA impedance network, S parameters and impedance circle. Derivation leads to the LNA matching condition reached the maximum gain of LNA and TVS caused by impedance mismatch is analyzed. Through the design of LNA (3), a typical impedance network simulation and experimental verification, the additional load effect of TVS on the LNA impedance network caused. With the aid of ADS (Advanced De Sign System) simulation software, a typical LNA transistor circuit design, and as the experimental object. This paper analyses the calculation of the required impedance network, load impedance assessment in the TVS network, the simulation results were compared with the experimental results. (4) design engineering application program of two, according to the parasitic parameter TVS is introduced to suppress the negative effects, so that LNA can effectively avoid the TVS and ESD current impact. Theoretical analysis and experimental results show that the introduction of TVS and LNA network load impedance at the same level, will work normally on LNA for destabilizing effects. In the design and RF circuit ESD the use of TVS, need to consider the parasitic parameters of TVS itself. This paper gives the improvement measures, although the gain level can not completely restore the LNA, but also can provide engineers way in ESD protection circuit design of TVS. The influence of radio frequency matching network has great engineering application value.

【学位授予单位】：南京师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN03;TN722.3

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