Multi-channel CMOS ASIC preamplifiers for APD and MSGC readouts

A 10-channel (Ch) and a 16-Ch application specific integrated circuit (ASIC) preamplifier chip with telescopic-cascode topology and gain-boosted folded-cascode topology respectively has been designed for avalanche photodiode (APD) and microstrip gas chamber (MSGC) readouts. These highly integrated and reliable chips can be used for individual readout from many channels to improve the spatial resolution and counting rate of such detectors over light sharing or charge division schemes. These chips were fabricated on a 2.4 mm times 2.4 mm die area using ROHM 0.35 mu CMOS technology. The chips were tested to have a low optimum equivalent noise charge (ENC) of about 880 e^-. The gains of the 10-Ch and 16-Ch preamplifiers are (1.4-pF)^-1 and (1.1-pF)^-1 while the rise times are 15 s and 13 s respectively. The 16-Ch chip was used to readout GSO-APD detectors and an optimum energy resolution of 11.3% (551 keV peak of Na-22) was obtained while the coincidence time resolution with a BaF₂ detector is about 11.5 ns. The energy resolution of Fe-55 with a 3 times 3 cm MSGC plate is about 20.5%.