A DISCRIMINATOR AND SHAPER CIRCUIT REALIZED IN CMOS TECHNOLOGY FOR BABAR

An analog chip is designed to receive from a PM, through a 50 Ohm coax ial cable, signals rising in 3 ns, falling in 8 ns, and to provide: di gital signals for timing purposes, multiplixed analog output, proporti onal to the input, for spectral measurements; there are 8 channels per chip with a common gain adjustment for the preamplifier, and individu al control for the offset and threshold setting. The discriminator sen sitivity is 2 mV. The dynamic range is from 2 to 100 mV. The noise equ ivalent at the input is approximate to 100 mu V. The RMS time dispersi on is less than 550 ps for 3 mV threshold. The shaping amplifier is of bipolar shape with 80 ns peaking time and 2.5 V mean output voltage. The cross talk between channels is less than 2%. (C) 1998 Elsevier Sci ence B.V. All rights reserved.