AMPLEX-SiCAL: a large dynamic range low-noise CMOS signal processor for silicon calorimeters

An analog signal processor using commercial 3- mu m CMOS technology has been designed and produced for the silicon luminosity calorimeter SiCAL of the ALEPH experiment. The authors present the results and the analysis of the various tests that have been performed on the circuit. This processor is a modified version of the AMPLEX integrated circuit designed for the inner silicon detector of the UA-2 experiment. The output voltage swing has been increased to more than 5.5 V are required for the large dynamic range of 1000 MIPs or 3.8 pC/sup 2/. A fast analog summation, based on a neural network principle called follower aggregation, computes the average input charges for triggering purposes. This chip contains 16 channels, with a charge amplifier, shaper, track-and-hold stage, multiplexer, fast analog sum, and a calibration system. The power consumption of the overall chip was 100 mW. The equivalent noise charge was less than 0.13 MIP for a 50 pF detector capacitance, and the peaking time was about 250 ns.< >