Abstract
In this thesis, a readout integrated circuit (ROIC) with adaptive transimpedance control (ATC) amplifier for Infrared Focal Plane Arrays (IR FPAs) is presented. The proposed ATC readout circuit consists of a front-end transimpedance amplifier (TIA) with an adaptive feedback capacitance. The output signal is fed to a comparator which determines a set of gain code (S0~S1) to control the feedback capacitance selected from a capacitor array. The capacitive transimpedance amplifier (CTIA) provides a stable bias for low-noise and low-leakage operation of IR sensor. It has the advantages in noise rejection, gain control, dynamic range, uniformity, and linearity. The column-shared Correlated Double Sample (CDS) circuit is utilized to eliminate the KTC noise and offset non-uniformity of the readout circuit. A CMOS image sensor chip with 32 x 32 pixel array and 30 x 30μm2 pixel size has been designed and fabricated in 0.18μm CMOS technology. The functions and superior readout performance of the proposed ATC readout circuit have been verified by experimental measurement at 1.8V supply. The chip area occupies 1.8 mm x 1.8 mm. It achieves a 24dB improvement of dynamic range, a frame rate of 175 fps, a power-per-pixel of 5μW/pixel and the total power of 5.5mW, respectively. It is shown that a high-performance readout circuit for IRFPA with high charge sensitivity, widely dynamic range and low power is realized. These advantageous traits make the readout circuit suitable for the various applications.