Very Wide Dynamic Range ROIC With Pixel-Level ADC for SWIR FPAs

Abstract

This paper describes a new wide dynamic range readout circuit incorporating a pixel-level time-to-digital analogto- digital converter for a short-wavelength infrared InGaAs focal plane array. To extend the dynamic range, the self-controlled integration capacitance technique and the detector current adaptive integration time technique are adopted in the readout circuit, which is operated individually in each pixel. Each pixel can have an appropriate gain independently depending on the signal current without any help from a digital processor. The readout circuit was fabricated using a 0.35-mu m standard CMOS process. The measured results of the fabricated chip show that the dynamic range exceeds 140 dB and that the noise level is 73.35 e-rms