IC-PIX28: A 28nm read-out channel for pixel detector

An Integrated Chip prototype for PIXel read-out, named IC-PIX28 and designed in 28nm CMOS technology, is here presented. The chip features a single channel including a cascade of a Charge-Sensitive-Amplifier (CSA) and a comparator, performing a Time-over-Threshold (ToT) operation. The IC-PIX28 comparator can operate with thresholds ≥3mV, generated on-chip starting from an off-chip reference voltage. A few number of transistors allows processing an input charge within 0.1fC÷5fC range. With the minimum input charge, the CSA output peak voltage is 4.6mV reached in 11ns. In this condition, 44mV/fC sensitivity and 0.029fC (180e-) Equivalent-Noise-Charge (ENC) are achieved with 4.67μA current consumption and 0.07mm² area occupancy.