A 70-$mu$ m Pitch 8-$mu$ W Self-Biased Charge-Integration Active Pixel for Digital Mammography

摘要

This paper presents a new low-power compact CMOS active pixel circuit specifically optimized for full-field digital mammography. The proposed digital pixel sensor (DPS) architecture includes self-bias capability at ${pm}$10% accuracy, up to 15 nA of dark-current autocalibration, built-in test mechanisms, selectable ${rm e}^-/{rm h}^+$ collection, 10-b lossless charge-integration analog–to-digital conversion, more than 1 decade of individual gain tuning for fixed pattern noise cancellation, and a 50-Mb/s digital-only input/output interface. Experimental results for a 70-$mu$m pitch 8-$mu$W DPS cell example are reported in 0.18-$mu$ m CMOS 1-polySi 6-metal technology.