A 12.5 Gb/s 0.13-μm CMOS inductorless transimpedance amplifier with 1 pF input capacitance for optical communications

This paper proposes an inductorless fully differential transimpedance amplifier (TIA) with a single-ended photo current to offer high bandwidth for applications of beyond 10 Gb/s optical communications. The presented TIA provides a much lower input impedance by modifying the cross-coupled regulated cascode (CC-RGC) configuration. The introduced method is able to enhance the bandwidth in the presence of wide range of input photodiode capacitance from small to large values, with a negligible increase in the peaking of frequency response. The proposed circuit is designed and simulated using the TSMC 130-nm CMOS technology to validate the proposed technique. The post-layout simulation results show that the TIA delivers a transimpedance gain of 46.5 dB Omega, a bandwidth of 8.8 GHz, and an input-referred current noise of 33 pA/root Hz. The circuit occupies an active area of 0.004 mm(2) and consumes 9.8 mW from a 1.3 V supply. Furthermore, the robustness of the proposed TIA is verified by means of the Monte Carlo simulations.