Low-noise monolithic bipolar front-end for silicon drift Detectors

A very low noise, 32-channel preamplifier/shaper chip has been designed for the analogue readout of silicon detectors. The circuit has been optimized in view of the operation of silicon drift detectors, which have very low ca pacitance and produce gaussian signals of sigma of few tens of ns. The chip (OLA) has been designed and manufactured using the SHPi full-custom bipola r process by Tektronix. Each channel is composed by a preamplifier, a shaper and a symmetrical line driver, which allows to drive either a positive and a negative single ende d output separately on 50 Omega impedance or a differential twisted pair. T he intrinsic peaking time of the circuit is similar to 60 ns, and the noise is below 250 electrons at zero input load capacitance. The power consumpti on is 2 mW/channel, mostly due to the output driver. (C) 1999 Elsevier Scie nce B.V. All rights reserved.