A Low-Noise Power-Efficient Stacked Differential Transimpedance Amplifier in 0.18-μm CMOS

This paper presents a stacked differential CMOS Transimpedance Amplifier (TIA) with DC-coupled connections to the cathode and anode of a photodiode (PD). It receives naturally differential signals from both ends of the PD, achieving a gain that is twice that of conventional single-ended TIA while reducing the input-referred noise by a factor of $\sqrt{ } 2$. Additionally, by employing voltage domain stacking to reuse the current, the circuit allows for reverse biasing of the PD and improves energy efficiency from 55% to ${9 7 \%}$. We have validated the feasibility of this TIA topology using a $0.18-\mu \mathrm{m}$ CMOS process. The implemented TIA operates with a conventional 3.3 V supply voltage, consuming 89.1 mW, and features a differential gain of $70 \mathrm{~dB} \Omega$, an input-referred noise of $7.09 \mathrm{pA} / \sqrt{ } \mathrm{Hz}$, and a 3-dB bandwidth of 6 GHz. To the authors’ best knowledge, this is the first differential TIA for DC coupling with single-ended PD.