126 dB High Dynamic Range SPAD Frontend for Time of Flight Applications

This letter presents a compact pixel frontend utilizing thin-oxide-only transistors paired with RC-coupled SPAD manufactured in a 3D-stacked technology. The frontend employs an optimized CMOS inverter operated close to its threshold to improve the sensitivity to low-amplitude SPAD pulses observed in a high light conditions close to device paralysis. This allows to achieve a dynamic range of 126dB and a maximum count rate of 117 Mcps ideal for automotive LiDAR or other ToF applications requiring tolerance to high background irradiance levels.