Design Methodology for Smear Suppression of Column Readout Circuit in CMOS Image Sensor

The column readout circuit in CMOS image sensor is highly integrated analog circuit arranged for each column of pixels in general. Due to the degree of integration, crosstalk between columns is likely to occur, resulting in deterioration in image quality. However, the integration of circuit components is limited in column floor plan, so that countermeasures unique to high integration is required. In this paper, various causes of smear, which is a typical image noise, in the readout circuit and its countermeasures are discussed.