A 10-GHz Bandwidth Transimpedance Amplifier With Input DC Photocurrent Compensation Loop

Abstract

A transimpedance amplifier (TIA) fabricated in a 55-nm low-power CMOS process is presented. The TIA, a current-reuse regulated cascode (CRRGC) topology, includes an active balun and differential output drivers. To maximize integration in high-speed photoreceivers, the TIA also includes dc current compensation, removing the requirement for bias-tees between the TIA and the photodiode (PD). The TIA achieves a transimpedance gain of 69 dB $\Omega $ across a 3-dB bandwidth of 10.7 GHz. Additionally, the TIA demonstrates low-noise performance with an equivalent input noise density of 15 pA/ $\sqrt {{\mathrm {Hz}}}$ in the passband. The dc compensation is capable of providing a fixed bias voltage for a PD while sourcing up to 2.4 mA or sinking up to 1 mA of photocurrent. The TIA, including active balun and dc current compensation, consumes 15.7 mW, while the output buffer consumes 90.7 mW. The total active area of the circuit is 0.07 mm2, and 0.21 mm2 with pads.