A Complementary Metal-Oxide Semiconductor (CMOS) Analog Optoelectronic Receiver with Digital Slicers for Short-Range Light Detection and Ranging (LiDAR) Systems

This paper introduces an analog differential optoelectronic receiver (ADOR) integrated with digital slicers for short-range LiDAR systems, consisting of a spatially modulated P⁺/N-well on-chip avalanche photodiode (APD), a cross-coupled differential transimpedance amplifier (CCD-TIA) with cross-coupled active loads, a continuous-time linear equalizer (CTLE), a limiting amplifier (LA), and dual digital slicers. A key feature is the integration of an additional on-chip dummy APD at the differential input node, which enables the proposed ADOR to outperform a traditional single-ended TIA in terms of common-mode noise rejection ratio. Also, the CCD-TIA utilizes cross-coupled PMOS-NMOS active loads not only to generate the symmetric output waveforms with maximized voltage swings, but also to provide wide bandwidth characteristics. The following CTLE extends the receiver bandwidth further, allowing the dual digital slicers to operate efficiently even at high sampling rates. The LA boosts the output amplitudes to suitable levels for the following slicers. Then, the inverter-based slicers with low power consumption and a small chip area produce digital outputs. The fabricated ADOR chip using a 180 nm CMOS process demonstrates a 20 dB dynamic range from 100 μA_pp to 1 mA_pp, 2 Gb/s data rate with a 490 fF APD capacitance, and 22.7 mW power consumption from a 1.8 V supply.