The high level of accumulated expertise by ULIS and CEA/LETI on uncooled microbolometers made from amorphous
silicon enables ULIS to develop ¼ VGA IRFPA formats with 17μm pixel-pitch to enable the development of small
power, small weight (SWAP) and high performance IR systems. ROIC architecture will be described where innovations
are widely on-chip implemented to enable an easier operation by the user. The detector configuration (integration time,
windowing, gain, scanning direction...), is driven by a standard I²C link. Like most of the visible arrays, the detector
adopts the HSYNC/VSYNC free-run mode of operation driven with only one master clock (MC) supplied to the ROIC
which feeds back pixel, line and frame synchronizations. On-chip PROM memory for customer operational condition
storage is available for detector characteristics.
Low power consumption has been taken into account and less than 60 mW is possible in analog mode at 60 Hz and <
175 mW in digital mode (14 bits). A wide electrical dynamic range (2.4V) is maintained despite the use of advanced
CMOS node. The specific appeal of this unit lies in the high uniformity and easy operation it provides. The reduction of
the pixel-pitch turns this TEC-less ¼ VGA array into a product well adapted for high resolution and compact systems.
NETD of 35 mK and thermal time constant of 10 ms have been measured leading to 350 mK.ms figure of merit. We
insist on NETD trade-off with wide thermal dynamic range, as well as the high characteristics uniformity and pixel
operability, achieved thanks to the mastering of the amorphous silicon technology coupled with the ROIC design. This
technology node associated with advanced packaging technique, paves the way to compact low power system.