155Mb/s光通信用CMOS自动增益控制跨阻前置放大器

采用华润上华的0.6μm标准CMOS工艺设计了一种应用于光纤通信系统STM-1速率级别的自动增益控制(AGC)跨阻前置放大器.为了扩展输入动态范围,采用自动增益控制技术监控输入电流中与电流幅度成正比的直流分量的变化.当输入信号过大时,降低电路的跨阻增益,从而避免输出波形出现严重失真.通过分析电路中几个主要元件对等效输入噪声电流的贡献,给出了噪声性能优化的方法.测试结果表明,在5V电源电压下,小信号时电路差分跨阻增益达到91.7dBΩ(38.5kΩ),-3dB带宽125MHz,最大输入光功率0dBm,平均等效输入噪声电流谱密度为4.8pA.功耗为180mW.芯片面积为0.7×0.4mm².

155Mb/s Automatic Gain Control CMOS Transimpedance Preamplifier for Optical Communication

A transimpedance preamplifier with automatic gain control (AGC) for 155Mb/s optic-fiber communication was designed and realized in CSMC 0.6 μ m standard CMOS technology.For the extension of input dynamic range,uses automatic gain control technique to monitor the variation of input dc component which is proportional to the magnitude of input current.When input current is large,transimpedance gain decreases to avoid output distortion.After analyzing contributions to equivalent input noise current of several elements in the circuit,gives a method of noise performance optimization.The measured results show that the pre-amplifier has differential transimpedance of 91.7dB Ω (38.5k Ω ),-3dB bandwidth of 125MHz,optical overload of 0dBm and average equivalent input noise current density of 4.8pA.Its power consumption is 180mW under single 5V power supply and the die area is 0.7×0.4mm².