A small area charge sensitive readout chain with a dual mode of operation

A charge sensitive readout chain has been designed and fabricated in commercial available 0.8 μm CMOS technology. The readout chain is optimized for soft X-ray pixel detectors measuring energies up to 20 keV. The dual mode of operation is controlled by external digital signal. There is the ability of generating either an analog voltage signal proportional to input charge or a voltage step with the same amplitude of previous signal, if a holding feature is required. The readout chain consists of a charge amplifier, a shaper, an operational amplifier which can either operates as a voltage amplifier or a peak detector and an output buffer. The designed area is 270 μm×150 μm. The gain at the shaper output is 378 mv/fC, the ENC is 16 e^- r.m.s. at 160 ns shaping time. The overall gain is 557 mV/fC, the ENC is 13 e^- r.m.s. with 240 ns peaking time and 1.4 μs recovery time. The overall power dissipation is 1.5 mW with a load capacitance of 25 pF