A high-speed 2nV/Hz1/2 16-channel current amplifier IC for PET

A 16 channel front-end IC dedicated to small animal positron emission tomography has been developed for cross-strip CdTe detectors. Each channel, designed to handle up to 20 pF detector capacitance, includes both low voltage (2 nV/Hz^1/2) and low current (40 fA/Hz^1/2) noise, high bandwidth (50 MHz at 20 pF detector capacitance) current amplifier with a gain of 100 for a power consumption of 4.7 mW. Both anode and cathode connection to the detector are possible thanks to an external control signal selecting the input common polarity. Input has been designed for maximum peak current of +/-1 A. Additional ¿charge amplifier¿ functionality is available via a single external control pin, extending functionality to X-ray or gamma-ray detection, fast instrumentation. Circuit size is 2×8 mm² in 0.35 ¿m 3.3 V CMOS process. Each channel differential output is buffered by a transconductance amplifier with two balanced differential current outputs compliant with 50 Ohm terminations.