Experimental characterization of a 10 μW 55 μm-pitch FPN-compensated CMOS digital pixel sensor for X-ray imagers

This paper presents experimental results obtained from both electrical and radiation tests of a new room-temperature digital pixel sensor (DPS) circuit specifically optimized for digital direct X-ray imaging. The 10 μW 55 μm-pitch CMOS active pixel circuit under test includes self-bias capability, built-in test, selectable e−/h+ collection, 10-bit charge-integration A/D conversion, individual gain tuning for fixed pattern noise (FPN) cancellation, and digital-only I/O interface, which make it suitable for 2D modular chip assemblies in large and seamless sensing areas. Experimental results for this DPS architecture in 0.18 μm 1P6M CMOS technology are reported, returning good performance in terms of linearity, 2kerms− of ENC, inter-pixel crosstalk below 0.5 LSB, 50 Mbps of I/O speed, and good radiation response for its use in digital X-ray imaging.