  ANTARES is a high-energy neutrino telescope installed in the Mediterranean
Sea at a depth of 2475 m. It consists of a three-dimensional array of optical
modules, each containing a large photomultiplier tube. A total of 2700
front-end ASICs named Analogue Ring Samplers (ARS) process the phototube
signals, measure their arrival time, amplitude and shape as well as perform
monitoring and calibration tasks. The ARS chip processes the analogue signals
from the optical modules and converts information into digital data. All the
information is transmitted to shore through further multiplexing electronics
and an optical link. This paper describes the performance of the ARS chip;
results from the functionality and characterization tests in the laboratory are
summarized and the long-term performance in the apparatus is illustrated.
