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. 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, 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 420nm, making it suitable for positron-emission tomography. Measurement results of the time-to-digital converter indicate a resolution of 128ps LSB with a differential non-linearity and integral non-linearity of -1/+5LSB and -2.4/+0.9LSB, 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 fast terminal 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.