一种带AGC功能的RGC输入前置放大器设计

摘要

This paper designs an RGC input pre-amplifier with AGC function of optical receiver based on 0.18 μm CMOS technology.The structure of circuits is the voltage parallel negative feedback.Its input stage is an RGC structure to expand bandwidth,which solves contradiction between wide bandwidth and high trans-impedance.The output stage is a single-to-differential structure.And in order to solve the contradiction between the dynamic range and high trans-impedance or low noise,the AGC circuit is used.Finally,the SIMC 0.18 μm technology library is selected to simulate.The results show that this circuit structure has good frequency characteristics and the equivalent current input curve,when input optical power of optical receiver is-10 dBm,the power supply voltage is 1.8 V,and the parasitic capacitance CD of the optical detector is 0.5 pF.%基于标准CMOS 0.18 μm工艺,设计了一种带AGC功能的光接收机RGC输入前置放大器.该放大器采用电压并联负反馈结构；输入级采用RGC结构以拓展带宽,从而解决了宽带宽与高跨阻之间的矛盾；输出级接入单端转差分结构,使输出的信号能直接输入到后续的主放大器中；嵌入自动增益控制技术AGC,以解决输入动态范围与高跨阻、低噪声之间的矛盾.同时,选用SIMC0.18 μm工艺库进行了模拟仿真.结果显示,当光接收机输入光功率为-10 dBm、电源电压为1.8V、光检测器的寄生电容为0.5 pF时,此放大器具有良好的等效电流输入曲线和幅频特性.