Low-Noise Broadband CMOS TIA Based on Multi-Stage Stagger-Tuned Amplifier for High-Speed High-Sensitivity Optical Communication

Abstract

Constrained by the transimpedance limit, the conventional 1-stage shunt-feedback transimpedance amplifier (1S-SF-TIA) suffers poor noise and gain at higher data rates. In this paper, we propose to use a multi-stage stagger-tuned amplifier (MSTA) to constitute TIA (MSTA-TIA), which not only transcends the transimpedance limit of 1S-SF-TIA, but also realizes noise reduction in multiple fronts. First, the high-gain MSTA enables 17X TIA gain over 1S-SF-TIA, which effectively suppresses the white noise. Second, the MSTA realizes at least 2.8X~1.6 lower noise than the conventional multi-stage amplifier, which is essential to form low-noise TIA since the amplifier noise usually dominates. Third, the TIA built upon the 3-stage STA also shows steeper out-of-band roll-off to enable high-frequency noise reduction. Overall, the MSTA-TIA achieves 6.9X and 1.9X noise power reduction over conventional single-stage and multi-stage SF-TIAs. As a demonstration, a 10 Gb/s optical receiver front-end prototype employing proposed MSTA-TIA topology is implemented in a standard $0.18~\mu \text{m}$ CMOS technology. It achieves transimpedance gain of 68.3dB $\Omega $ , electrical bandwidth of 8.5GHz, and excellent input-referred noise current of $0.97~\mu $ Arms. The chip occupies 0.78 mm2 while consuming 43 mA from 1.8 V power supply. The low-noise design methodology in this paper empowers mature CMOS to compete with SiGe to make low-noise high-gain optical IC.