A Multifunction Snapshot ROIC Design for Low and High Background Application

A snapshot infrared read out circuit (ROIC) with multifunction and very wide dynamic range was presented in the paper. The merits of the ROIC include small layout area, CTIA (capacitive transimpedance amplifier) integrator, selectable integration capacitors, adjustable operation bandwidth and anti-blooming. Through the snapshot mode and adjustable integration time from 1μs to 33ms (calculated by 30Hz frame frequency), the dynamic range can be extended efficiently, which provides high and low background operation abilities to the whole system. Based on the Gray code theory, random window access, dynamic image transposition, and 1, 2, 4 selectable channel outputs, can be realized by digital control circuits of the ROIC. The 32×32 array with pixel area of 30×30μm² was successfully manufactured by 0.35μm CMOS process of HHNEC. The design also can be used in large format infrared focal plane array (IRFPA), such as 320×240, 640×480, etc.