一种用于1.25Gbps光接收机的跨阻放大器设计

Design of Transfer Impedance Amplifier Chip for 1.25 Gbps Optical Receivers

给出了一种用于1.25 Gbps光接收机的跨阻放大器(TIA,Transfer Impedance Amplifier)设计。该TIA采用电阻并联反馈形式。为保证TIA在PVT (Process, Voltage, Temperature)变化范围较大时较一致的带宽和增益,设计了自适应带宽控制电路来稳定带宽。为满足较宽的动态范围,通过自动增益控制电路(AGC)控制增益。该TIA采用0.18μm CMOS工艺进行设计,实测结果表明,在输入端光电二极管电容CPD为0.7 pF时,TIA的增益为12.0 kΩ,带宽达0.96 GHz,总噪声电流为104 nA,满足1.25 Gbps光接收机的指标要求。

A transfer impedance amplifier(TIA) for 1.25 Gbps is proposed in the paper.Resistive shunt feedback architecture is used in TIA design.Adaptive bandwidth control circuit is used to stabilize bandwidth in PVT(Process,Voltage,and Temperature) conditions.Automatic gain control is also designed for higher dynamic range.The proposed TIA is designed and simulated based on 0.18 μm CMOS process.When the capacitance of photodiode is 0.7 pF,simulation results of the proposed TIA show gain of 12.0 kΩ,bandwidth of 0.96 GHz,total noise current of 104 nA.The proposed TIA meets the requirements of 1.25 Gbps optical receiver.