A 9.8 μm sample and hold time to amplitude converter CMOS SPAD pixel

Abstract

A 9.8μm pitch SPAD-based pixel is presented with a novel and scalable Sample and Hold (S/H) Time to Amplitude Converter (TAC) pixel architecture offering the potential to create high spatial resolution Time Correlated Single Photon Counting (TCSPC) image sensors in the future. This pixel pitch is an order of magnitude smaller than previous TCSPC pixels. The NMOS-only TAC performance is measured in a single point TCSPC optical experimental setup. 93ps LSB time resolution is obtained over 80ns dynamic range. Dynamic range limitations are discussed and improvements are suggested.