A low power, low noise, ultra-wide dynamic range CMOS imager with pixel-parallel A/D conversion

Abstract

A CMOS image sensor with pixel-parallel A/D conversion fabricated with different array sizes and photodiode types in a 3-metal 0.5 /spl mu/m process is presented. Nominal power dissipation is 40 nW per pixel at V/sub DD/=3.3 V. A/D conversion results from sampling a free-running photocurrent-controlled oscillator to give a first-order /spl Sigma/-/spl Delta/ sequence. The sensor displays dynamic range capability of greater than 150000:1 and exhibits fixed pattern noise correctable to within 0.1% of signal.