设计了一款应用于无源光网络(PON)的突发模式激光驱动器及其双环功率控制电路。提出一种电荷补偿和动态偏置电路,减小了激光驱动器电流上升和下降时间,提高了输出电流能力;提出一种双环功率控制的反馈电路,解决了平均功率和消光比随温度变化的问题。基于0.18μm RF CMOS工艺完成流片,激光驱动器芯片面积为1 600μm×800μm。测试结果表明,激光驱动器的输出偏置电流和调制电流分别可达90 m A。激光驱动器突发响应开启时间小于2 ns,关断时间小于1 ns,发送数据速率高达2.5 Gbit/s,抖动大小为41 ps。激光驱动器输出平均光功率稳定性为±0.26 d B,消光比稳定性为±1 d B。该激光驱动器满足了PON系统对激光器的输出功率和稳定性要求。
This paper describes the design and analysis of a fully differential,gain-enhanced CMOS telescopic operational transconductance amplifier （OTA） used in a pipeline analog-to-digital converter （ADC）. Specifications of the OTA are derived from the requirements of ADC. Simulation shows that for a lpF load capacitance, this OTA achieves a high DC gain （approximately 145dB） and a wide unity-gain bandwidth （above 750MHz） at a phase margin 58°. In a configuration where the closed loop-gain is 4,the design spends about 18ns for settling with 0.05% accuracy. Simulations of this design are performed in SMIC CMOS 0.18μm technology.
