Characterization of polybenzimidazole (PBI) film at high temperatures

Polybenzimidazole, a linear thermoplastic polymer with excellent thermal stability and strength retention over a wide range of temperatures, was evaluated for its potential use as the main dielectric in high temperature capacitors. The film was characterized in terms of its dielectric properties in a frequency range of 50 Hz to 100 kilo-Hz. These properties, which include the dielectric constant and dielectric loss, were also obtained in a temperature range from 20 C to 300 C with an electrical stress of 60 Hz, 50 V/mil present. The alternating and direct current breakdown voltages of silicone oil impregnated films as a function of temperature were also determined. The results obtained indicate that while the film remained relatively stable up to 200 C, it exhibited an increase in its dielectric properties as the temperature was raised to 300 C. It was also found that conditioning of the film by heat treatment at 60 C for six hours tended to improve its dielectric and breakdown properties. The results are discussed and conclusions made concerning the suitability of the film as a high temperature capacitor dielectric

Operation of a New Half-Bridge Gate Driver for Enhancement - Mode GaN FETs, Type LM5113, Over a Wide Temperature Range

A new commercial-off-the-shelf (COTS) gate driver designed to drive both the high-side and the low-side enhancement-mode GaN FETs, National Semiconductor's type LM5113, was evaluated for operation at temperatures beyond its recommended specified limits of -40 C to +125 C. The effects of limited thermal cycling under the extended test temperature, which ranged from -194 C to +150 C, on the operation of this chip as well as restart capability at the extreme cryogenic and hot temperatures were also investigated. The driver circuit was able to maintain good operation throughout the entire test regime between -194 C and +150 C without undergoing any major changes in its outputs signals and characteristics. The limited thermal cycling performed on the device also had no effect on its performance, and the driver chip was able to successfully restart at each of the extreme temperatures of -194 C and +150 C. The plastic packaging of this device was also not affected by either the short extreme temperature exposure or the limited thermal cycling. These preliminary results indicate that this new commercial-off-the-shelf (COTS) halfbridge eGaN FET driver integrated circuit has the potential for use in space exploration missions under extreme temperature environments. Further testing is planned under long-term cycling to assess the reliability of these parts and to determine their suitability for extended use in the harsh environments of space

Evaluation of a Programmable Voltage-Controlled MEMS Oscillator, Type SiT3701, Over a Wide Temperature Range

Semiconductor chips based on MEMS (Micro-Electro-Mechanical Systems) technology, such as sensors, transducers, and actuators, are becoming widely used in today s electronics due to their high performance, low power consumption, tolerance to shock and vibration, and immunity to electro-static discharge. In addition, the MEMS fabrication process allows for the miniaturization of individual chips as well as the integration of various electronic circuits into one module, such as system-on-a-chip. These measures would simplify overall system design, reduce parts count and interface, improve reliability, and reduce cost; and they would meet requirements of systems destined for use in space exploration missions. In this work, the performance of a recently-developed MEMS voltage-controlled oscillator was evaluated under a wide temperature range. Operation of this new commercial-off-the-shelf (COTS) device was also assessed under thermal cycling to address some operational conditions of the space environmen

Performance of an SOI Boot-Strapped Full-Bridge MOSFET Driver, Type CHT-FBDR, under Extreme Temperatures

Electronic systems designed for use in deep space and planetary exploration missions are expected to encounter extreme temperatures and wide thermal swings. Silicon-based devices are limited in their wide-temperature capability and usually require extra measures, such as cooling or heating mechanisms, to provide adequate ambient temperature for proper operation. Silicon-On-Insulator (SOI) technology, on the other hand, lately has been gaining wide spread use in applications where high temperatures are encountered. Due to their inherent design, SOI-based integrated circuit chips are able to operate at temperatures higher than those of the silicon devices by virtue of reducing leakage currents, eliminating parasitic junctions, and limiting internal heating. In addition, SOI devices provide faster switching, consume less power, and offer improved radiation-tolerance. Very little data, however, exist on the performance of such devices and circuits under cryogenic temperatures. In this work, the performance of an SOI bootstrapped, full-bridge driver integrated circuit was evaluated under extreme temperatures and thermal cycling. The investigations were carried out to establish a baseline on the functionality and to determine suitability of this device for use in space exploration missions under extreme temperature conditions

Stability of a Crystal Oscillator, Type Si530, Inside and Beyond its Specified Operating Temperature Range

Data acquisition and control systems depend on timing signals for proper operation and required accuracy. These clocked signals are typically provided by some form of an oscillator set to produce a repetitive, defined signal at a given frequency. Crystal oscillators are commonly used because they are less expensive, smaller, and more reliable than other types of oscillators. Because of the inherent characteristics of the crystal, the oscillators exhibit excellent frequency stability within the specified range of operational temperature. In some cases, however, some compensation techniques are adopted to further improve the thermal stability of a crystal oscillator. Very limited data exist on the performance and reliability of commercial-off-the-shelf (COTS) crystal oscillators at temperatures beyond the manufacturer's specified operating temperature range. This information is very crucial if any of these parts were to be used in circuits designed for use in space exploration missions where extreme temperature swings and thermal cycling are encountered. This report presents the results of the work obtained on the operation of Silicon Laboratories crystal oscillator, type Si530, under specified and extreme ambient temperatures

Operation of a New COTS Crystal Oscillator - CXOMHT over a Wide Temperature Range

Crystal oscillators are extensively used in electronic circuits to provide timing or clocking signals in data acquisition, communications links, and control systems, to name a few. They are affordable, small in size, and reliable. Because of the inherent characteristics of the crystal, the oscillator usually exhibits extreme accuracy in its output frequency within the intrinsic crystal stability. Stability of the frequency could be affected under varying load levels or other operational conditions. Temperature is one of those important factors that influence the frequency stability of an oscillator; as it does to the functionality of other electronic components. Electronics designed for use in NASA deep space and planetary exploration missions are expected to be exposed to extreme temperatures and thermal cycling over a wide range. Thus, it is important to design and develop circuits that are able to operate efficiently and reliably under in these harsh temperature environments. Most of the commercial-off-the-shelf (COTS) devices are very limited in terms of their specified operational temperature while very few custom-made commercial and military-grade parts have the ability to operate in a slightly wider range of temperature than those of the COTS parts. These parts are usually designed for operation under one temperature extreme, i.e. hot or cold, and do not address the wide swing in the operational temperature, which is typical of the space environment. For safe and successful space missions, electronic systems must therefore be designed not only to withstand the extreme temperature exposure but also to operate efficiently and reliably. This report presents the results obtained on the evaluation of a new COTS crystal oscillator under extreme temperatures

Operation of SOI P-Channel Field Effect Transistors, CHT-PMOS30, under Extreme Temperatures

Electronic systems are required to operate under extreme temperatures in NASA planetary exploration and deep space missions. Electronics on-board spacecraft must also tolerate thermal cycling between extreme temperatures. Thermal management means are usually included in today s spacecraft systems to provide adequate temperature for proper operation of the electronics. These measures, which may include heating elements, heat pipes, radiators, etc., however add to the complexity in the design of the system, increases its cost and weight, and affects its performance and reliability. Electronic parts and circuits capable of withstanding and operating under extreme temperatures would reflect in improvement in system s efficiency, reducing cost, and improving overall reliability. Semiconductor chips based on silicon-on-insulator (SOI) technology are designed mainly for high temperature applications and find extensive use in terrestrial well-logging fields. Their inherent design offers advantages over silicon devices in terms of reduced leakage currents, less power consumption, faster switching speeds, and good radiation tolerance. Little is known, however, about their performance at cryogenic temperatures and under wide thermal swings. Experimental investigation on the operation of SOI, N-channel field effect transistors under wide temperature range was reported earlier [1]. This work examines the performance of P-channel devices of these SOI transistors. The electronic part investigated in this work comprised of a Cissoid s CHT-PMOS30, high temperature P-channel MOSFET (metal-oxide semiconductor field-effect transistor) device [2]. This high voltage, medium-power transistor is designed for geothermal well logging applications, aerospace and avionics, and automotive industry, and is specified for operation in the temperature range of -55 C to +225 C. Table I shows some specifications of this transistor [2]. The CHT-PMOS30 device was characterized at various temperatures over the range of -190 C to +225 C in terms of its voltage/current characteristic curves. The test temperatures included +22, -50, -100, -150, -175, -190, +50, +100, +150, +175, +200, and +225 C. Limited thermal cycling testing was also performed on the device. These tests consisted of subjecting the transistor to a total of twelve thermal cycles between -190 C and +225 C. A temperature rate of change of 10 C/min and a soak time at the test temperature of 10 minutes were used throughout this work. Post-cycling measurements were also performed at selected temperatures. In addition, re-start capability at extreme temperatures, i.e. power switched on while the device was soaking for a period of 20 minutes at the test temperatures of -190 C and +225 C, was investigated

Performance Evaluation of an Automotive-Grade, High Speed Gate Driver for SiC FETs, Type UCC27531, Over a Wide Temperature Range

Silicon carbide (SiC) devices are becoming widely used in electronic power circuits as replacement for conventional silicon parts due to their attractive properties that include low on-state resistance, high temperature tolerance, and high frequency operation. These attributes have a significant impact by reducing system weight, saving board space, and conserving power. In this work, the performance of an automotive-grade high speed gate driver with potential use in controlling SiC FETs (field-Effect Transistors) in converters or motor control applications was evaluated under extreme temperatures and thermal cycling. The investigations were carried out to assess performance and to determine suitability of this device for use in space exploration missions under extreme temperature conditions

Low Temperature Characterization of Ceramic and Film Power Capacitors

Among the key requirements for advanced electronic systems is the ability to withstand harsh environments while maintaining reliable and efficient operation. Exposures to low temperature as well as high temperature constitute such stresses. Applications where low temperatures are encountered include deep space missions, medical imaging equipment, and cryogenic instrumentation. Efforts were taken to design and develop power capacitors capable of wide temperature operation. In this work, ceramic and film power capacitors were developed and characterized as a function of temperature from 20 C to -185 C in terms of their dielectric properties. These properties included capacitance stability and dielectric loss in the frequency range of 50 Hz to 100 kHz. DC leakage current measurements were also performed on the capacitors. The manuscript presents the results that indicate good operational characteristic behavior and stability of the components tested at low temperatures

Third NASA Workshop on Wiring for Space Applications

This workshop addressed key technology issues in the field of electrical power wiring for space applications, and transferred information and technology related to space wiring for use in government and commercial applications. Speakers from space agencies, U.S. Federal labs, industry, and academia presented program overviews and discussed topics on arc tracking phenomena, advancements in insulation materials and constructions, and new wiring system topologies