Radiation-hardened and wide-temperature mixed-signal/RF electronics development is aligned, per NASA OCT Technology Area TA08, with the major flight programs within the Planetary Science Division: Discovery 13/14, New Frontiers 4, Lunar Quest, Mars Exploration, Outer Planets Programs, and Europa Jupiter System Mission. Components based on state-of-the-art, 90-nm SiGe technology will help reduce the volume, mass, and power requirements of instrument electronics, essential to maximizing the science return for future missions. Electronics capable of operating in extreme environments will enable science missions currently thought to be impractical due to the requirement of bulky protective housing. Electronic parts are getting smaller with technology evolution and the radiation/temperature effects are becoming more severe. A robust physics-based capability to predict the behavior of electronic circuits increases mission confidence. Radiation-hardened and wide-temperature analog, mixed-signal, and RF circuits are essential for ALL avionic systems used in NASA exploration missions. The RHBD designs from this project will add to the NASA "components library" for extreme environment applications. The physics-based mixed-mode tools will help NASA better evaluate the wide-temperature performance and radiation response at an early stage, and design rad-hard low-temperature electronics with better understanding and control of design margins, thereby reducing the test time and cost. Various critical analog, mixed-signal, and RF circuits are used in all space-based platforms, including DoD space systems (communication, surveillance, ballistic missiles, missile defense), and commercial satellites. Since modern electronics technologies and components are becoming increasingly sensitive to extreme environments, the capability to predict their behavior can dramatically increase mission confidence and reduce risk. The new RHBD designs and circuit/cell libraries, based on the best-in-class SiGe technology, offer reduced size-weight-and-power and cost (SWaP-C) to all aerospace applications. The physics-based computer aided design (CAD) tools can also be applied to cryogenic electronics for high-sensitivity, low-noise analog and mixed-signal applications, such as metrology, infrared (IR) imagers, sensors (radiation, optical, X-ray), radiometrology, precision instruments, radio and optical astronomy, infrared and photon detectors, and other high-end systems. For all such devices and systems, predictive and accurate modeling and design tools reduce the amount of required radiation/temperature testing, thus decreasing their cost, and time to market or field application.