Novel current-mode background suppression for 2-D LWIR applications

Abstract

A new readout circuit involving two-step current-mode background suppression is studied for two-dimensional long-wavelength infrared focal plane arrays (2-D LWIR FPAs). Buffered direct injection (BDI) and a feedback amplifier are used for the input circuit and background suppression circuit, respectively. The readout circuit has been fabricated using a 0.6-mu m 2-poly 3-metal CMOS process for a 64 x 64 LWIR HgCdTe IR array with a pixel size of 50 mu m x 50 mu m. The simple pixel circuit has a very small skimming error of less than 0.3% and low noise characteristics for an adequate calibration range and integration time.