Noise performance of readout electronics for photodetector

A 16 channel integrated circuit charge sensitive preamplifier (CSA) has been developed for an X-ray detector module that uses a 16 linear arrays of photodetector. The photodiode is made of 280 um thickness, 30 M Omega shunt resistivity, the measured junction capacitance 200 pF. The main performances of the CSA for photodetector 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 us by external passive components. The noise simulation yield ENC values of 50 e(-) and 250 e(-) for thermal and 1/f noise, respectively. The design was fabricated in standard 0.35 um CMOS technology and the circuit occupies an area of 4 x 4 mm2 and dissipates 2 mW per channel from a 3.3 V single power supply.