Noise analysis of 16 channel charge sensitive amplifier for poly CZT

A 16 channel integrated circuit charge sensitive preamplifier (CSA) has been developed for an X-ray detector module that uses a 16 linear array of poly CZT. The polycrystalline CdZnTe:Cl thick films used in this experiment have 1.2times10¹⁰ Omegacm in resistivity, 150 mum in thickness. The main performances of the CSA for this poly CZT are the following: the input equivalent noise charge is 300 e^- rms at peaking time 200 ns, the highest gain is 10 mV/fC, the peaking time is adjustable between 50 ns and 300 mus by external passive components. The noise simulation yielded ENC values of 50e^- and 250e^- for thermal and 1/f noise, respectively. The design was fabricated in standard 0.35 mum CMOS technology and the circuit occupies an area of 4times4 mm² and dissipates 2 mW per channel from a 3.3 V single power supply.