Design of a transimpedance amplifier with high gain and low noise

The cascode structure and inductor peaking technology can make the transimpedance amplifier have a higher bandwidth, and the parallel-parallel negative feedback circuit structure can achieve a higher gain. A 25Gbit/s optical receiver front-end transimpedance amplifier circuit is designed based on 0.18μm SiGe BiCMOS technology. For a practical photodiode, the circuit reasonably achieves a compromise between gain, bandwidth and noise when the parasitic capacitance is as high as 140fF. After simulation and testing, the transimpedance gain of the circuit is 62.6dBΩ, the -3dB bandwidth is 14.9GHz, the equivalent input noise current within the -3dB bandwidth is less than 9.03pA/√Hz, and the power consumption is 23.5mW.