Blumino is the first analog silicon photomultiplier with integrated amplifier, comparator and time-To-digital converter (TDC). The combination of a photodetector together with on-chip readout circuitry enables system-level advantages, such as internal parasitic reduction, compactness and simplicity. The analog silicon photomultiplier has a third output, called fast terminal (FT), in addition to the anode and cathode, which is used for timing measurements. The analog silicon photomultiplier presents excellent photon detection efficiency greater than 40% at 420 nm, making it suitable for positron-emission tomography. Measurement results of the TDC indicate a resolution of 128 ps least significant bit (LSB) with a differential nonlinearity and integral nonlinearity of-1/+5 LSB and-2.4/+0.9 LSB, respectively. The discriminator comprises two preamplifier stages followed by a complementary self-biased differential amplifier stage which is coupled to the analog silicon photomultiplier's FT through a decoupling capacitor. The sensor is also fully backward-compatible through the standard output which can be coupled to dedicated ASICs and standard readout integrated circuits. In addition to the electrical, radiation, and optical performance, the integration of a custom CMOS analog silicon photomultiplier process with standard CMOS process was investigated.

We present a design that implements digitization of an analog SiPM's fast output on chip to pave the way to higher granularity in the digital conversion of photon detection. The design comprises a comparator bank, time-to-digital converters (TDCs), and electronics for interfacing with the external world. The TDC is a multipath, gated ring oscillator with a counter and phase detector, implemented in 0.35μm CMOS technology. Simulation results indicate a DNL of ±0.55LSB and an INL of ±1LSB, a large, adjustable range, and a typical resolution of 65ps (LSB).