IR sensor readout devices with source input circuits

Abstract

High performance IR imaging systems for, e. g., surveillance and reconnaissance applications, are currently basically include focal plane arrays (FPAs) with multielement scanning or staring two-dimensional matrix of PV detectors cooled down to cryogenic temperatures with a signal processor. The FPA technologies mainly include two major technologies, hybrid and monolithic. The concept of the IR FPA hybrid technology is widespread as it permits separate optimization of the parameters of the detector array with a large number of sensitive elements and typical silicon readout device coupled with the detector array [1]. The major hybrid technology uses mercury-cadmium-telluride (MCT) PV detectors and silicon CCD or CMOS chips [1, 2] for readout and multiplexing of the stored charge from the detectors; there are a lot of various designs of such interface but practically they are the source coupling or gate coupling ones [3-5]. Performance requirements for IR FPAs are considerably varied with respect to the wavelength region, background photon radiation, operating temperature, dynamic range, noise, readout rate, power dissipation, detector biases, and some other parameters. IR FPAs are mainly clustered in atmospheric window wavelength ranges 1-2.5, 3-5, 8-12 µm, and depending on the wavelength region applied, they are aimed at T ≈ 250300, 77150, 2090 K operating temperatures, respectively. The primary function of a readout device for IR arrays is to provide an IR detector charge to voltage conversion, integration of the electrons generated in photodetector, preliminary signal processing, e.g., skimming, partitioning, amplification and time multiplexing of signals from the cooled detectors in the array [4] to much less number of outputs. In the case of scanning systems, TDI function should be used to improve performance of