A 0.88nW/pixel, 99.6 dB Linear-Dynamic-Range Fully-Digital Image Sensor Employing a Pixel-Level Sigma-Delta ADC

We describe a CMOS image sensor employing pixel-level SigmaDelta analog to digital conversion. The design has high fill factor (31%), zero DC offset fixed pattern noise and reduced reset and transistor readout noise in comparison to other analog and digital imager readout techniques. The SigmaDelta pixel design also has low power consumption: 0.88 nW/pixel at 30 fps, high dynamic range of 16 bits, intrinsic linearity, and relative insensitivity to process variations