A multi-channel integrated readout circuit chip for small capacitance sensors

The design, fabrication, and test results of a multi-channel integrated readout circuit (MIROC) mixed-signal ASIC for low capacitance (<;10pF) solid state sensors arrays are presented in this publication. The chip, fabricated in IBM 0.18 μm 7WL SiGe BiCMOS technology and measuring 4 × 4 mm, contains nineteen analog amplifier channels with pulse-shaping and peak-and-hold detection, three on-chip 8-bit hybrid ADCs, each equipped with an 8-bit parallel-to-serial shift register, and digital control logic for routing any of the channels with a hit to any available ADC. As a highly integrated system requiring minimal external controls, the chip was designed with the intention of significantly reducing cost, volume, power, and mass of the readout system for related applications, and consequently should reduce the development cycle of new instruments. MIROC has a FWHM noise below 20keV. Each channel contains four configurable conversion gain levels, measured to be 3.73mV/fC, 8.59mV/fC, 13.89mV/fC and 21.59mV/fC. In case of silicon detectors, the chip is capable of studying energetic charged particles over the range from 100keV to 6MeV. Measured test results and key characteristics are presented in the paper.