A high-dynamic range ROIC for SLS and other IR focal planes

In many high dynamic range applications, Sigma-Delta modulator (SDM) architectures have displaced most other architectures for analog to digital conversion (ADC). SDMs have not typically been applied to ROIC applications due to the interaction of spatial discontinuities and the temporal bandwidth limitation of the SDM. By using a novel serpentine readout sequence, we have reduced the temporal bandwidth and enabled application of SDM technology for high dynamic range Focal Plane Arrays (FPA). In addition, it is reconfigurable on-the-fly for a power vs. Signal to Noise plus Distortion Ratio (SNDR) tradeoff without “binning” or reducing the pixel pitch. This technique has been applied to enable low power foveal imaging. This reconfigurable ADC has been coupled with a low noise extended dynamic range photodiode input stages.