14.3-bit extended counting ADC with built-in binning function for medical X-ray CMOS imagers

Proposed is a 14.3-bit extended counting analogue-to-digital converter (ADC) with built-in binning function for medical X-ray CMOS imagers. To reduce the area and improve the image resolution simultaneously, the proposed ADC internally performs the analogue binning operation without a charge amplifier. The ADC also uses an extended input range to realise true 14-bit dynamic range when applying the digital correlated double sampling technique. The proposed ADC was fabricated using a 0.35 m CMOS process and the measured differential and integral nonlinearities of the 14.3-bit ADC are 0.97/ 0.79 and 2.79/ 1.70 LSB, respectively.