A transimpedance CMOS multichannel amplifier with a 50 /spl Omega/-wide output range buffer for high counting rate applications

A fast transimpedance multichannel amplifier has been designed, fabricated in CMOS 1.2-/spl mu/m technology and tested. Each channel consists of a current sensitive preamplifier followed by a voltage amplification stage and an on-chip buffer able to drive 50 /spl Omega/ loads with an output range of /spl plusmn/800 mV. Measured peaking time at the output is 40 ns and the circuit recovers to baseline in 90 ns. This results in a counting capability of more than 10/sup 7/ hits/s, Signals of both polarities can be handled. The first two stages consume a total of 2 mW per channel and the 50 /spl Omega/ buffer consumes another 17 mW. The equivalent noise charge (ENC) is 1100 e/sup -/ rms with a slope of 40e/sup -//pF. The IC is intended for use in gas and solid-state detectors with high particle rate and extensive charge release as in high energy calorimetry.