A 16-Channel Analog CMOS SiPM With On-Chip Front-End for D-ToF LiDAR

This article presents a 16-channel analog silicon photomultiplier (SiPM) with on-chip front-end for direct time-of-flight (D-ToF) LiDAR applications. The proposed receiver is mainly composed of 16-channel SiPM, variable gain amplifier (VGA) and time-to-digital converter (TDC). Each SiPM channel consists of 256 microcells, and their outputs are connected to a common output terminal in parallel. A novel active quenching circuit is adopted to reduce the long exponential tail in conventional SiPM and enable the capability of multi-echo detection. Current steering circuits are adopted within microcells to make the output current of SiPM immune to SPAD gain variations. The receiver was fabricated in 180-nm HV CMOS technology and integrated into the 16-line LiDAR prototype with optical components. Measurement results show that the sensor is capable of 20 m range imaging with 3 cm accuracy under 40 klux background light conditions. With the mechanical scanning system, a high-resolution image (240 x 16) can be obtained.