A pipelined multiranging integrator and encoder ASIC for fast digitization of photomultiplier tube signals

A new full custom chip is being designed using the Orbit 2 micron ''BiCMOS'' process to provide a wide range fast digital readout of Photomultiplier Tubes. The goal is to obtain a digitized PMT signal with a 18--20 bit dynamic range and 8 bits of accuracy in a floating point number format every 16 ns. The chip is DC coupled to a PMT and uses a four-way gated integrator and encoder to form a 4 bit binary number which is the exponent of the floating point number. Simultaneous processing of the PMT signal on binary weighted scales provides a pipelined analog signal to a single FADC which generates the floating point number mantissa. The current state of development of this new chip and results from several test chips are presented in this paper. 3 refs