High Speed Comparator for Single-Photon Avalanche Photodiode

A high speed comparator applied to GHz gated single photon detection technology is proposed. The comparator is based on the combination of pre-amplification and dynamic regenerative latching structures, resulting in an effective improvement in response speed. In this paper, an analysis on the transmission delay of the dynamic latch comparators is presented. The proposed circuit is implemented in 350 nm CMOS technology and occupies an active area of 0.012mm(2). The delay of the whole detection system is approximately 256ps and the discrimination level of the proposed comparator is 50mV while consuming 4.7mW at supply voltages of 3.3V. The comparator can be used in a single photon gated detection system under 1 GHz condition.