A Current-Mode Optoelectronic Receiver IC for Short-Range LiDAR Sensors in 180 nm CMOS

Abstract

This paper presents three different types of on-chip avalanche photodiodes (APDs) realized in a TSMC 180 nm 1P6M RF CMOS process, i.e., a P+/N-well (NW) APD for its high responsivity and large bandwidth by excluding slow diffusion currents; a P+/Deep N-well (DNW) APD for its improved near-infrared (NIR) sensitivity; and a P+/NW/DNW APD for its capability to prevent premature edge breakdown and improve NIR sensitivity. Thereafter, a conventional voltage-mode optoelectronic receiver (V-OER) was realized to confirm the feasibility of the three on-chip APDs. However, the measured results of the V-OER demonstrate a very narrow dynamic range. Therefore, we propose a current-mode optoelectronic receiver (C-OER) realized in the same CMOS process for the applications of short-range LiDAR sensors, where current-conveyor input buffers are exploited to deliver the photocurrents with no significant signal loss to the following inverter cascode transimpedance amplifier, hence resulting in an extended dynamic range. The optically measured results of the C-OER with an 850 nm laser source demonstrate large output pulses. The C-OER chip consumes 47.8 mW from a 1.8 V supply and the core occupies 0.087 mm2.

Keywords

• avalanche photodiode
• CMOS
• current-mode
• LiDAR
• mirrored-cascode
• optoelectronic