CMOS有源电感并联的前馈共栅跨阻放大电路

Feedforward common gate transimpedance amplifier circuit based on CMOS active inductor in parallel

设计了一种改进的前馈共栅 (Modified Feedforward Common Gate, MFCG) 跨阻放大电路,通过使用 CMOS 有源电感与前馈共栅 (Feedforward Common Gate, FCG) 跨阻放大电路中的共源放大级并联,使跨阻放大电路的带宽和跨阻增益均得到有效提升。基于 TSMC 60 nm CMOS 工艺在Cadence 软件平台对 MFCG 跨阻放大电路进行仿真分析和版图设计。仿真结果表明在电源电压为 1.8 V,光电二极管结电容为 200 fF 的情况下,放大电路的-3 dB 带宽为 17.2 GHz,跨阻增益为 55 dBΩ,在带宽内等效输入噪声电流谱密度小于 55pA√Hz,电路功耗为 3.7 mW,电路版图面积为 0.002 9 mm^(2)。结果表明:所设计的 MFCG 跨阻放大电路具有跨阻增益高、带宽大、版图面积小等优点,可用于 20 Gb/s光纤通信系统的光接收机电路。

A modified feedforward common gate transimpedance amplifier circuit was designed. By using CMOS active inductor in parallel with the common source amplifier stage in the feedforward common gate transimpedance amplifier circuit, the bandwidth and gain of the transimpedance amplifier circuit can be improved effectively. Based on TSMC 60 nm CMOS process, simulation analysis and layout design of MFCG crossresistance amplifier were carried out on Cadence software platform. The simulation results show that when the power supply voltage is 1.8 V and the photodiode junction capacitance is 200 fF, the amplifier circuit’s-3 dB bandwidth is 17.2 GHz, the transimpedance gain is 55 dBΩ, the equivalent input noise current spectral density isless than 55pA√Hz in the bandwidth, and the circuit power consumption is 3.7 mW. The circuit layout area is0.002 9 mm2. The results show that the designed MFCG transimpedance amplifier has the advantages of high transimpedance gain, large bandwidth, small layout area and so on, and can be used in the optical receiver circuit of 20 Gb/s fiber communication system.