Push broom multi-band Focal Plane Assembly (FPA) design needs to consider optics, image sensor, electronic, mechanic as well as thermal. Conventional FPA use two or several CCD device as an image sensor. The CCD image sensor requires several high speed, high voltage and high current clock drivers as well as analog video processors to support their operation.
Signal needs to digitize using external sample / hold and digitized circuit. These support circuits are bulky, consume a lot of power, must be shielded and placed in close to the CCD to minimize the introduction of unwanted noise. The CCD also needs to consider how to dissipate power. The end result is a very complicated FPA and hard to make due to more weighs and draws more power requiring complex heat transfer mechanisms.
A five-band CMOS Sensor (dedicated as C468) was designed for push broom FPA used on Remote Sensing Instrument (RSI) application. The CMOS Sensor, allow for the incorporation of clock drivers, timing generators, signal processing and digitization onto the same Integrated Circuit (IC) as the image sensor arrays. This keeps noise to a minimum while providing high functionality at reasonable power levels. The C468 is a first Multiple System-On-Chip (MSOC) IC. This device used our proprietary wafer butting technology and MSOC technology to combine five long sensor arrays into a size of 120 mm x 23.2 mm and 155 mm x 60 mm for chip and package, respectively. The device composed of one Panchromatic (PAN) and four different Multi-Spectral (MS) sensors. Due to its integration on the electronic design, a lot of room is clear for the thermal design. The optical and mechanical design is become very straight forward. The flight model FPA passed all of the reliability testing and flight proven on-board Remote Sensing Instrument (RSI) of FORMOSAT-5 launched in August 2017.