【作者】 张小军；

【导师】 喻明艳；

【作者基本信息】 哈尔滨工业大学 ， 微电子学与固体电子学， 2007， 硕士

【摘要】 随着社会的发展,信息交换量与日俱增。近年来,以光波为载体、光纤为传输媒质的光纤通信异军突起,发展十分迅速,已成为信息高速公路的主体。光纤通信具有容量大、传输距离远、节省能源、抗干扰、抗辐射等诸多优点,开发具有自主知识产权、用于光纤传输的高速集成电路对我国的信息化建设具有重大意义。在用于光纤传输系统的几个功能电路中,构成光接收机前端放大电路的前置放大器是其中的一个关键电路。本课题的任务是采用HJTC0.18μm CMOS(3.3V器件,最小沟道长度为0.34μm)工艺实现适用于光纤传输系统国际同步数字体系的STM-8速率级(1.25Gbps)的前置放大器。作为光接收机的关键部分,前置放大器的性能在很大程度上决定了整个光接收机的性能。在高速光纤传输系统中,广泛采用跨阻前置放大器。本文采用三级反相放大器级联的跨阻放大器作为前置放大器的核心部分。利用SPICE仿真软件对前置放大器进行模拟,仿真结果显示:等效输入噪声电流谱密度为22.122pA/√Hz@940MHz,输入为2.51μA时,等效输入噪声电流为0.21μA ,灵敏度为-26dBm ,跨阻增益达到了65dB? ,带宽为976MHz,差分输出相位差为180°。整个前置放大器工作电压3.3V,包括DC-DC模块、跨阻放大器、自动增益控制、单端-双端转换等四个主要模块。为适应光纤传输信号的大动态范围需要,采用自动增益控制电路控制跨阻放大器的反馈电阻,以实现增益可调的形式来有效控制输出信号范围;单端-双端转换将跨阻放大器的单端输出转换为差动输出,以方便与后级的主放大器连接。最后,完成了前置放大器的版图设计并提取了寄生参数,进行了后仿真。仿真结果与前仿真符合较好,很好地完成了电流到电压的转换,信号的放大和差动输出功能。更多还原

【Abstract】 With the rapid development of telecommunication networks, computer networks and Internet, it is urgent to build information super-highway. Optic-fiber communication systems are the principal parts of information super-highway for its merits such as great capacity, long transmit distance, economizing energy source, anti interference and anti radiation etc. Thus, it is very important to design high speed integrated circuits for optical transmission systems with independent property.In the building blocks of an optical transmission system, the pre-amplifier is one of the critical parts. The task of this project is to design a pre-amplifier for SDH STM-8(1.25Gbps) optical receiver using HJTC0.18μm(the device power supply is 3.3V, and the smallest effective channel length is 0.34μm) CMOS technology.The performance of pre-amplifier has great effect on the performance of optical receiver. Transimpedance pre-amplifiers is widely used in the high speed optical transmission systems. In this design, the transimpedance amplifier is configured on three identical stages as the core circuit of the pre-amplifier. The simulated results are presented finally with the help of SPICE software tool, and that show the performance of the pre-amplifier, equivalent input noise current density of 22.122 pA/√Hz @940MHz, equivalent input noise current is 0.21μA as the input signal current of 2.51μA, and the sensitivity is -26dBm, transimpedance of 65 dB?, bandwidth of 976MHz, and the differential output phase is different of 180o.The pre-amplifier plays its best performance when power supply is 3.3V. It includes these modules: DC-DC block, transimpedance amplifier, Automatic Gain Controller, Single to differential conversion circuits etc. In order to meet the requirement of optical communication single which have a large dynamic range, we adopte the AGC circuit to control the feedback resistance of the trans-impedance that regulate the gain of the transimpedance. That can control the output amplitude. Single to differential conversion circuits convert the single output of the transimpedance to differential output. That can easily connect the post-amplifier. In this paper, the design of the whole layout is finished, and the layout parameter is extracted. The validity of this CMOS pre-amplifier circuit is proved by the results of simulation. Current to voltage conversion, signal amplifying and differential output are realized very well.更多还原