A radiation-hard, low-background multiplexer design for spacecraft imager applications

Abstract

One of the Cassini Mission science and environmental requirements for the Visible and Infrared MappingSpectrometer is a custom multiplexer design for the infrared focal plane. The multiplexer input unit cell must be designed for a low-background application because of the low albedos of the planned objects for imaging. A radiation-hard design process is necessary to ensure device survivability in the radiation environments enroute to and at Saturn. A multiplexer design that meets these primary requirements has been proposed. The design and electrical operation of this multiplexer will be discussed.

Design considerations of ROIC for single color LWIR and multicolor IR focal plane arrays

“…The gate is connected to the output of the differential amplifier while the source to the negative input, the external bias to the other differential input. In doing so the input impedance is decreased by a significant factor due to the feedback properties and the injection efficiency is close to unity (10,11).…”

Low-Power CMOS Digital Pixel Imagers for High-Speed Uncooled PbSe IR Applications

“…In the case of large IR staring-FPAs, straightforward input topologies like source follower per detector (SFD) [31][32][33][34][35], direct injection (DI) [36][37][38][39] and gate modulation input (GMI) [31,40] are still popular because of their compactness and reduced power consumption [19]. Other complex circuit techniques like buffered direct injection (BDI) [36,41] and capacitive transimpedance amplifier (CTIA) [42][43][44]39] offer higher performance by providing excellent bias control, high injection efficiency, linearity and lower noise figures. More recent structures like share-buffered direct injection (SBDI) [45], switched-current integrator (SCI) [46] and buffered gate modulation input (BGMI) [47] are intended to provide better compromise between pixel size constraints and readout performance.…”

Focal-plane-arrays and CMOS readout techniques of infrared imaging systems

“…Some simple readout structures like source-follower per detector (SFD) [45], [46], direct injection (DI) [47]- [49], and gate-modulation input (GMI) [45], [50] are still commonly used in large staring IR FPA's because of the small pixel area and power consumption. In addition, more complex circuit techniques like buffered direct injection (BDI) [47], [51] and capacitive transimpedance amplifier (CTIA) [52], [53] have been developed to provide excellent bias control, high injection efficiency, linearity, and noise performance. Simple and highperformance circuit techniques have been a challenging work in the design of readout circuits for IR FPA's.…”

“…5) Capacitive Transimpedance Amplifier [52], [53]: The schematic of the capacitive transimpedance amplifier (CTIA) is shown in Fig. 8 where the integration capacitor is placed on the feedback loop of the amplifier with a reset device M-Rst to discharge the integration capacitor and reset the amplifier output to the reference voltage .…”