High Slew-Rate Quadruple-Voltage Mixed-Quenching Active-Resetting Circuit for SPADs in 0.35-μm CMOS for Increasing PDP
An optical sensor IC in 0.35-<inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> CMOS is presented containing a single-photon avalanche diode (SPAD) and a fast quadruple-voltage quenching circuit (QVQC). The QVQC features a fast active quenching time of 0.93 ns, a total quenching time of 1.9 ns, and an adjustable total dead time (8.6–200 ns) to reduce the afterpulsing probability (APP). To verify the quenching performance, the circuit was integrated with a 40-<inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> diameter SPAD. Experiments show the reduction of afterpulsing by a low detection threshold and by fast quenching with a slew rate of 13.8 GV/s. Thus, an APP of 3.2% at 27-ns dead time, a peak photon detection probability (PDP) of 67.6% at 652 nm, and a PDP of 34.7% at 854 nm were measured at 13.2-V excess bias.