Paper
2 February 2004 Focal plane readout for 2-D LWIR application implemented with current mode background suppression per pixel
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Abstract
In this paper, a readout technique involving current mode background suppression is studied for 2-dimensional infrared focal plane arrays (IR FPA’s). This technique has a current memory per pixel, and the suppression current can be optimized per pixel element. Capacitive transimpedende amplifier (CTIA) and feedback amplifier structure are adopted for input circuit and background suppression circuit, respectively. Feedback amplifier structure can minimize skimming error due to channel length modulation. The area size of the pixel circuit is generally limited in the case of 2-D application. So, the amplifier used in the CTIA input circuit adopts timesharing for background suppression. To further improve the area limitation, a half circuit of the CTIA is shared in row circuit out of the pixel array. Because of the leakage of the current memory, the skimming data of the current memory in the pixel array is stored in SRAM array through ADC, and is refreshed periodically with SRAM data through DAC. The readout circuit was fabricated using 0.6um 2-poly 3-metal CMOS process for 64 x 64 LWIR HgCdTe IR array with the pixel size of 50um x 50um. The measurement performance of the skimming circuit exhibits about only 3% error for 100nA background current. The simulation results exhibit that skimming error can be reduced further to 0.3% when the ratioed current mirror scheme and/or multi step refresh scheme is adopted.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Doo Hyung Woo, Sang Gu Kang, and Hee Chul Lee "Focal plane readout for 2-D LWIR application implemented with current mode background suppression per pixel", Proc. SPIE 5234, Sensors, Systems, and Next-Generation Satellites VII, (2 February 2004); https://doi.org/10.1117/12.514157
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KEYWORDS
Sensors

Amplifiers

Long wavelength infrared

Staring arrays

Infrared detectors

Infrared radiation

Transistors

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