Noise analysis and comparison of analog and digital readout integrated circuits for infrared focal plane arrays

We analyze the traditional analog ROIC architecture and an oversampled Sigma-Delta modulator/decimator architecture. We show how the latter has superior characteristics i.e. an improved maximum signal to noise ratio (SNR_MAX). This is a result of effectively increasing the well capacity by a factor equal to the oversampling ratio (OSR). We also provide a high fidelity noise model for both an analog and the digital ROIC and show that the equivalent electron noise at the output of the digital ROIC is much less compared to the traditional analog ROICs.