Current-Mode Dark-Level Subtraction in LWIR Imaging

A complementary metal oxide/semiconductor (CMOS) focal-plane readout circuit for an imaging array of long-wavelength infrared (LWIR) photodetectors effects in-pixel current-mode subtraction of the dark-level component of each photodetector output. The dark-level signal is subtracted before the signal reaches the integration node. Consequently, for each pixel in the array, the readout noise is minimized and the net gain and dynamic range are maximized.