A LIDAR sensor prototype with embedded 14-bit 52 ps resolution ILO-TDC array

High resolution light detection and ranging (LIDAR) systems enable rapid imaging and mapping for applications such as autonomous vehicles and robotics. This paper presents a high-resolution LIDAR sensor system-on-a-chip (SoC) prototype containing a 31 × 2 pixel channel array with the input time-of-flight resolved by a 32 × 1 time-to-digital converter (TDC) array. A low-power avalanche photodiode (APD) receiver front-end with output bit-line sharing allows an array implementation and achieves − 22 dBm sensitivity. Injection-locked oscillators (ILOs) are utilized in a TDC design to both minimize clock distribution power and improve timing accuracy. An on-chip phase-looked loop calibrates for ILO global PVT variations and ensures reliability over a wide operating range. Fabricated in GP 65 nm CMOS, the 14-bit TDC consumes 788 μW/channel and achieves 52 ps resolution over an 830 ns full-scale range, 37.2 ps rms single-shot precision, 11 ps rms channel uniformity, and DNL/INL of 0.56/1.56 LSB, respectively. This electrical characterization projects that the SoC has the potential for 0.78 cm ranging precision over a 124 m maximum ranging distance. Sensor testing with a pulsed laser and an APD array hybrid-integrated with the CMOS SoC shows a measurement range of over 700 ns with a 3.2 ns maximum single-shot error.