A CMOS Image Sensor Pixel Combining Deep Sub-Electron Noise With Wide Dynamic Range
Assim Boukhayma, Antonino Caizzone, Christian Enz
Abstract
This letter introduces a 5-transistors (5T) implementation of CMOS Image Sensors (CIS) pixels enabling the combination of deep sub-electron noise performance with wide dynamic range (DR). The 5T pixel presents a new technique to reduce the sense node capacitance without any process refinements or voltage level increase and features adjustable conversion gain (CG) to enable wide dynamic imaging. The implementation of the proposed 5T pixel in a standard 180nm CIS process demonstrates the combination of a measured high CG of 250 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</sub> V/e and low CG of 115 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</sub> V/e with a saturation level of about 6500e offering photo-electron counting capabilitywithout compromising the DR and readout speed.