Realization of readout integrated circuit (ROIC) for an array of 72x4, P-on-N type HgCdTe long wave infrared detectors

Official URL: http://192.168.1.20/record=b1228185 (Table of Contents)

Infrared Focal Plane Arrays (IRFPAs) are important and high-tech systems, which are used in many strategic applications, such as medical imaging, missile guidance, and surveillance systems. The most important building blocks of IRFPAs are detectors and Readout Integrated Circuit (ROIC). Both of them need careful design and implementation for the overall system to be succesful. Detector part produces the photon induced current and sent to the input of ROIC. Detector design and fabrication determines the operating wavelength and main noise performance of the imaging system. On the other hand, ROIC is the interface element between the detector and microcomputer of the IRFPA system, and determines important performance parameters of the overall system; such as linearity, dynamic range, injection efficiency, noise performance (less effective than detector), and power consumption. Therefore it is important to design and implement a ROIC, that fits best to the desired application. In this thesis, a CMOS ROIC is designed and implemented for scanning type of 72×4 Pon- N HgCdTe detector array in 0.35 μm, 4 metal 2 poly AMS CMOS process. Current Mirror Integration (CMI) is used as the unit cell of the ROIC. For the signal processing, Time Delay Integration (TDI) over 4 elements with an optical supersampling rate of 3 is used for improved Signal-to-Noise Ration (SNR). The designed and implemented ROIC has the properties of bidirectional scanning, variable integration time, adjustable gain settings, bypass functionality, automatic gain adjustment, and pixel selection/deselection functionality. ROIC is programmable through a serial and a parallel interface. Gain settings, TDI scanning direction, information of mulfunctioning pixels, ROIC operation mode (test or TDI) can be programmed by using these interfaces. Operating frequency of the ROIC is up to 5 MHz, while the dynamic range is 2.8 V.