A Linear-Mode LiDAR Sensor Using a Multi-Channel CMOS Transimpedance Amplifier Array

This paper presents a linear-mode optical sensor for the feasible applications of unmanned vehicle LiDAR systems, in which a pulsed-erbium fiber laser is exploited as a light source and a 16-channel transimpedance amplifier (TIA) array is utilized in an optical Rx module with low-cost InGaAs PIN photodiodes. In particular, a voltage-mode CMOS feedforward (VCF-TIA) is newly proposed to achieve twice higher transimpedance gain with lower noise and similar bandwidth characteristics than a conventional inverter TIA, thereby enabling longer detection. Test chips of the 16-channel VCF-TIA array realized in a standard 0.18-\mu \text{m} CMOS process demonstrate 76.3-dB \Omega transimpedance gain, 6.3-pA/sqrt(Hz) average noise current spectral density, less than-33-dB crosstalk between channels, and 29.8-mW power dissipation per channel from a single 1.8-V supply. Automatic gain control is also equipped to extend input dynamic range for near-range detection. Hence, the proposed linear-mode optical sensor clearly detects the reflected optical pulses from the target of 5% reflection rate within the range of 0.5-25 m.