A CMOS application specific integrated circuit (ASIC) was developed for 3D Position Sensitive
Detectors (PSD). The preamplifiers were optimized for pixellated Cadmium-Zinc-Telluride (CZT)
Mercuric-Iodide (HgI2) and Thallium Bromide (TlBr) sensors. The ASIC responds to an ionizing
event in the sensor by measuring both amplitude and timing in the pertinent anode and cathode
channels. Each channel is sensitive to events and transients of positive or negative polarity and performs
low-noise charge amplification, high-order shaping, peak and timing detection along with analog
storage and multiplexing. Three methodologies are implemented to perform timing measurement
in the cathode channel. Multiple sparse modes are available for the readout of channel data. The ASIC
integrates 130 channels in an area of 12 x 9 mm2 and dissipates ~330 mW. With a CZT detector
connected and biased, an electronic resolution of ~200 e- rms for charges up to 100 fC was measured.
Spectral data from the University of Michigan revealed a cumulative single-pixel resolution of ~0.55
% FWHM at 662 KeV.