A low-power CMOS nine-channel 40-MHz binary detection system with self-calibrated 500-μV offset

For application in high-energy physics experiments, this paper describes the design of a nine-channel binary detection system featuring a fully differential 300-μW, 40-MHz comparator whose offset voltage is reduced to less than 500 μV by means of a digitally controlled calibration system. Besides the comparator, each channel also includes an input waveshaping high-pass filter for improved detection performance in the particle-radiated operating environment. To save area and power, this is realized by a passive switched-capacitor polyphase network with time-interleaved operation. Two prototype chips have been realized in a 1.2-μm CMOS technology. One chip includes nine filter-comparator channels that occupy 0.4 mm² and at 40 MHz dissipate about 2.7 mW. The other chip contains the calibration system that generates all control signals for offset correction of the filter/comparator channels and occupies 1.4 mm²