A small area charge sensitive readout chain with a dual mode of operation
A charge sensitive readout chain has been designed and fabricated in a commercially available 0.8 mum CMOS technology. The readout chain is optimized for pixel detectors measuring soft X-ray energies up to 20 KeV. In the first mode an analog signal proportional to input charge is generated and processed in real time. In the second mode a peak-and-hold operation is enabled and the relevant signal is processed in later time. This dual mode of operation is controlled by an external digital signal. The readout chain consists of a charge amplifier, a shaper, an operational amplifier which can either operate as a voltage amplifier or a peak detector and an output buffer. Its area is 270 mum 150 mum. The gain at the shaper output is 378 mv/fC, the ENC is 16 e(-) rms at 160 nsec shaping time. The overall gain is 557 mV/fC, the ENC is 13 e(-) rms with 240 nsec peaking time and 1.4 mu sec recovery time. The overall power dissipation is 1.5 mWatt with a load capacitance of 25 pF.
charge sensitive readout chain peak detector x-ray pixel detectors readout electronics 0.8 mu m cmos