Uncooled diode infrared detector and design of its readout interface circuit

A design for integration of diode infrared detectors based on SOI and its readout interface circuit was presented for the low cost and high performance applications of uncooled infrared technology. Basic principle and fabrication technology of uncooled diode infrared detectors were elaborated. Through theoretical derivation of the electrical characteristics of detectors, circuit design specifications were given. The circuit used continuous time auto-zero technique to reduce offset voltage and suppress low frequency noise. It amplified the signals and cascaded a filter to decrease effects of non-ideal switches. Capacitors in chip were chosen to sample and hold, and as a result, the layout of the circuit had fewer I/O pads and smaller area. It was simulated using spectre tool and fabricated in CSMC 0.5 m 2P3M CMOS process. Experimental results show that this circuit has a good performance, achieving a closed-loop gain of 65.8 dB, equivalent input noise power spectral density of 450 nV/Hz, equivalent input offset voltage smaller than 100 V and power consumption of 5 mW, can accurately read out the outputs of detectors.