A high-precision and high-linearity readout integrated circuit for infrared focal plane array applications

This paper proposes a readout integrated circuit (ROIC) with high precision and high linearity based on the standard capacitive transimpedance amplifier (CTIA) structure. A high-swing cascode current mirror is introduced, which can restrain the influence of the front-end unstable voltage on the integrating unit. Also, the high-swing cascode current mirror can reduce the influence of the integral nonlinear error caused by the finite gain of the amplifier on the bias point, which will significantly increase the linearity and reduced the nonlinear error of the output. Moreover, buffered direct injection method is adopted in the bias circuit in order to ensure the bias point stability and reduce the non-uniformity. A 4 x 2 experimental chip have been fabricated by adopting AMS 0.35 mu m CMOS process. The simulation and experimental results demonstrate the ROIC with the features of high linearity, high injection efficiency, stable bias point and low noise, which is suitable for high performance applications.