Blumino: The First Fully Integrated Analog SiPM With On-Chip Time Conversion

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.