A low-noise, extended dynamic range 1.3 megapixel InGaAs array

Abstract

Xenics has designed and manufactured a 1280*1024 pixel, 17 µm pitch InGaAs array for SWIR imaging in the [0.9 - 1.7 µm] range. It will report on the first characterization results of the device. As usual for this type of room temperature operated SWIR image sensors, the detector interface is based on a CTIA stage, yielding excellent linearity, a low detector bias and hence a low and stable dark current combined with low image lag. The charge to voltage conversion factor is 40 µV/e-. The pixel interface scheme contains a CDS circuit in order to reduce the kTC noise and common mode effects. The noise is expected to be below 30 e-rms in linear mode, resulting in a dynamic range < 60 dB. Additionally the linear dynamic range is complemented with a high dynamic range logarithmic response with a saturation level < 5 nA/pixel. The information in the pixel matrix can be read via 2, 4 or 8 outputs, yielding a maximum full frame rate between 50 and 200 Hz. Each output is operating at 40 MHz pixel rate. The outputs are differential with a common mode voltage of 0.9 V and an adjustable output swing of 2 Vptp. Nevertheless the power dissipation shall be below 330 mW.