Low Power Configurable Readout Integrated Circuit for Infrared Detector

In general, Readout Integrated circuits (ROICs) are made of using standard silicon technology to collect signals from the infrared photo detectors arrays. Design of the ROIC is challenging because we have to ensure that the performance of the whole system is limited by the detector and not by the read out circuitry. Read while integration (snapshot) type ROIC's are required for the critical applications like space, astronomy and defense. For snapshot type ROIC's integration time needs to be at least as much as that required for reading the full array. This may be too long and may saturate the input circuits. In order to avoid saturation of ROIC output, Windowing, i.e. reading of a selected window of programmable size from the focal plan array is useful. The implementation of the windowing feature requires programmable control signals for the pixel selection. In this paper we have proposed low power reconfigurable ROIC circuit for dynamic windowing. The selected window can be as small as 32 x 48 to the full array of 320 x 256. The design and post layout simulation results of ROIC test chip of 320x256 array of 30 mu m x 30 mu m pixel size in 180 nm, 3.3V compatible CMOS SCL process is discussed in this paper. Critical specifications are charge handling capacity of greater than 10 Me and low readout noise of less than 523 electrons, have been able to achieve at room temperature.