Mixed-Signal Silicon Photomultiplier With Reconfigurable Pulse Shaper for Background Light Rejection

This paper presents a mixed-signal Silicon Photomultiplier with integrated front-end, including a reconfigurable Pulse Shaper. Each Silicon Photon Avalanche Diode of the msSiPM converts a photon into a programmable current pulse. Then, all analog current signals are collected by a transimpedance amplifier which provides an output voltage proportional to the number of triggered SPADs. By properly tuning the shape of the current pulses, the proposed msSiPM rejects the background light and optimizes the Signal-to-Noise Ratio. As the architecture is mostly digital, msSiPM consumes a low static power consumption, equal to 428 $\mu $ W. The receiver is composed by a $20 \,\, \times 20$ -pixel array, and it is fabricated in a 0.11 $\mu $ m CMOS technology reaching a pixel fill factor equal to 32.8%. Measurements have been carried out under different background photon fluxes, one stronger and one weaker, corresponding to 4.15 and 2.15 GPhotons/s at the SiPM, demonstrating strong background rejection in both conditions. In addition, a SNR maximization has been verified. Analytical models for SNR and Signal-to-Background Ratio have been presented, showing a good matching with experimental results.