  PARISROC is a complete read out chip, in AMS SiGe 0.35 micron technology, for
photomultipliers array. It is a front-end electronics ASIC which allows
triggerless acquisition for the next generation of neutrino experiments. These
detectors have place in megaton size water tanks and will require very large
surface of photo-detection. An R & D program, funded by French national agency
for research and called PMm2, proposes to segment the very large surface of
photo-detection in macro pixels made of 16 photomultiplier tubes connected to
an autonomous front-end electronics. The ASIC allows triggerless acquisition
and only send out the relevant data by network to the central data storage.
This data management reduces considerably the cost of these detectors. This
paper describes the front-end electronics ASIC called PARISROC which integrates
totally independents 16 channels with a variable gain and provides charge and
time measurement with a 12-bit ADC and a 24-bits Counter.
