A ROIC for Diode Uncooled IRFPA With Hybrid Non-Uniformity Compensation Technique

A CMOS readout integrated circuit with nonuniformity calibration for diode uncooled infrared focal plane array (IRFPA) is presented in this paper. Pixel signals are sampled and held by a capacitor, eliminating the extra current of the reference pixel. We propose a new transconductance amplifier with offset cancellation structure, utilizing output offset voltage storage. A novel 8-b current splitting DAC array is proposed in this paper. With the help of an off-chip ADC, the bias current of each pixel can be adjusted by DAC array, calibrating the nonuniformity of the IRFPA. The proposed circuit with 32 readout channels is fabricated using a 0.35-μm standard CMOS process. The measured results show that the average output offset voltages are 600 and 40 mV before and after calibration, respectively. The non-uniformity calibration technique has been proven very effective with 95% offset decrement, and this paper is especially suitable for large-scale image sensor.