Radiation-hardened electronics technology remains stable amid steady demand in the space market

May 21, 2010
 Technology focus -- Despite the slow economy and proposed cancellation of NASA’s major human space flight program, the space electronics market is moving steadily along while exploring smaller and smaller form factors to increase performance. Meanwhile, the methods for radiation-hardening electronics remain the same.   

The economic downturn has affected many high-technology markets, but much like the military sector the space electronics market continues to prove resilient. Investment in new designs and new programs are steadily increasing and designers of radiation-hardened electronics (rad-hard) are optimistic midway through 2010 despite the recession and government cutbacks.

Programs that have been canceled the last few years include the Department of Defense’s Transformational Satellite Communications System (TSAT) and most recently NASA’s Constellation program, which includes the Ares 1 and Ares V rockets and the Orion crew exploration vehicle. This has had its influence on rad-hard electronics.

The cancellation of NASA Constellation could be troublesome but “should not manifest itself till early next fiscal year,” says Tony Jordan director of standard products, at Aeroflex Colorado Springs in Colorado Springs, Colo.

“Most new space platforms have been either cancelled or delayed,” says Keith Nootbaar, senior director of microelectronics and precision sensors at Honeywell Aerospace in Plymouth, Minn. “This has delayed the utilization of Honeywell’s newer technologies and products longer than we had anticipated. However, the first half of this year has seen several new space development programs being awarded, which has resulted in an increase in our 150 nanometer HX5000 ASIC (application-specific integrated circuit) implementations.

Honeywell, which is a major player in the Constellation program, is still moving forward as if the program will survive.

“Until a final budget is approved by Congress, it is inappropriate for Honeywell to speculate,” Nootbaar says. “However, our work continues on Orion, and Honeywell is integrally involved in command and data handling systems, displays and controls, navigation, systems engineering, and software for the Orion crew exploration vehicle."

Space programs tend to survive because their design schedules stretch out for so long. “The space market is strong regardless of the economy because the timelines to design and build a satellite -- sometimes more than five years -- are much longer than a typical economic downturn,” says Doug Patterson, vice president of sales and marketing at Aitech in Chatsworth, Calif. “Also, there are certain applications that always require space assets no matter what the economy is like such as TV broadcasting, mobile communication, imaging, etc.”

Much of the recent space market turmoil could be in the past. “The market seems steady right now and we just came through a unique cycle, which was a result of TSAT being canceled and having the Advanced Extremely High Frequency (AEHF) satellite and other programs still in their procurement phases,” Jordan says.

Robotic and deep-space missions for NASA are steady and “the turnover is pretty quick, which gives us buoyancy as well,” Jordan notes.

Another program important to Aeroflex is GPS III, which will provide improved Global Positioning System (GPS) satellite navigation worldwide. The industry is also expecting good things once the contract is awarded for Iridium Next, which will offer improved satellite network speeds and bandwidth for cellular service to the military and other users. The contract will go to either Lockheed Martin or Thales Alenia Space, Jordan adds.

Space applications have been strong for the last couple years, says Greg Overend sales and marketing manager at MS Kennedy Corp. in Milpitas, Calif. The commercial arena has been driven by high definition TV and the military by classified satellite programs such as GPS III, he adds.

The improving market conditions and new programs bode well for designers of rad-hard technology such as field programmable gate arrays (FPGAs), single-board computers (SBCs); memory, integrated circuits, power converters, and other devices.

Rad-hard technology trends

“The latest trend in radiation-harden electronics is in the area of high speed communications, especially for next generation space applications,” Nootbaar says. “The primary radiation hardened technology that is enabling this trend is Honeywell’s serializer/deserializer (SERDES) product and technology that improves the speed of serial data communication fifty-fold over existing radiation hardened space electronics.

“This technology includes both a discreet quad redundant SERDES product and an imbedded application-specific integrated circuit (ASIC) macro,” Nootbaar continues. “These SERDES product and macro allows for communications speeds up to 3.125 gigabytes per second per channel enabling standard communication protocols such as Gigabit Ethernet, 10 Gigabit Ethernet XAUI, and 10 Gigabit Fibre Channel XAUI.

“For space applications, we have seen high reuse of existing platforms requiring the need for older products,” Nootbaar continues. “Because of this demand we have maintained our 0.8-micron and 0.35-micron products and processes. This has opened up new opportunities for Honeywell as 5 volt product becomes obsolete, especially for field programmable gate arrays (FPGAs). We have been able to offer 5 volt compliant FPGA translations or obsolete part replacement utilizing our 0.8-micron process. We have successfully completed between 40 and 50 Actel FPGA replacements over the last five years with first pass success on all of the implementations. In addition, approximately one-third of these translations are flying.

“We are now starting to see non-radiation hardened military applications seeking the same 5 volt compliant capability for their older programs, especially with respect to ECL capable products,” Nootbaar continues. “Honeywell has been able to develop a proven CMOS based ECL I/O capability for these programs.”

Aeroflex’s focus today is with microprocessors, Jordan says. Aeroflex supplied a UT699-base LEON 3FT controller card to NASA Goddard Space Flight Center’s MISSE-7 (Materials International Space Station Experiment-7). MISSE-7 is a test bed for materials and coatings attached to the outside of the International Space Station.

The UT699 LEON 3FT controller board used Aeroflex’s UT699 LEON 3FT microprocessor along with memory, FPGA, and logic products – the UT8ER512K32 SRAM MCM with error detection and correction, the UT8R512K8 4 megabyte SRAM MCM, UT6325 Eclipse FPGA, and UT54ACS164245S logic. Two of Aeroflex’s clock products, the UT7R995 clock buffer, and their new UT7R2XLR816 clock network manager, are also on board, Jordan says.

The company’s acquisition of Gaisler Research in Goteborg, Sweden has enabled them also to develop microprocessor IP cores, he adds.

Rad-hard memory

In the rad-hard memory arena the main trend is toward larger densities.

“Larger density SRAMs and non-volatile memories” are in demand among system integrators, Nootbaar says. “Honeywell has two product development programs to address these requirements. The first program, which is nearing completion, is the development of a 64 megabyte SRAM module. This product uses four of Honeywell’s QML qualified 16 megabyte monolithic SRAMs and stacks them using a low profile die stacking methodology to produce a 64 megabyte SRAM that is the same footprint as the 16 megabyte SRAM. Engineering models are available now, with QML qualified flight units available the second half of this year.

“With respect to high density non-volatile memory, Honeywell has a program to develop a 16 megabyte monolithic MRAM (magnetic resistive, random access memory) based upon our success with the 1 megabyte MRAM that is currently available. The 16 megabyte MRAM will read and write like an SRAM, will have radiation assurance of greater than 1 megarad total dose, and capable of maintaining data for greater than 15 years without refresh. Like the 16 megabyte SRAM discuss previously, Honeywell plans to stack this product to create a 64 megabyte MRAM module for FPGA load applications. We are working with major SRAM based FPGA manufacturers to ensure that the design and communication structure is in alignment with their product requirements.

Honeywell’s newest memory product is the “4 Megabyte Rad-Tolerant SRAM -- with 300krads total dose,” Nootbaar says. “This is a new product developed by Honeywell that leverages our 150 nanometer process capability along with our silicon on insulator (SOI) process technology to provide a low priced 4 megabyte SRAM product for the larger market that does not need or can afford a 1 megarad product.”

The 4 megabyte RT SRAM provides access times of 15 nanoseconds (12 nanoseconds typical) at approximately 25 percent of the price and 20 percent of the active power of Honeywell’s 0.35-micron 4 megabyte SRAM, he adds.

Rad-hard power ICs

Users of rad-hard power integrated circuits (ICs) are looking for improved performance, higher power density, smaller size, lighter weight, and added functionality, says Odile Ronat, HiRel marketing manager at International Rectifier Corp. in El Segundo, Calif. “They sometimes have to place the power converter on the digital board to meet performance requirements.”

This presents a new challenge for the power designers and digital designers alike where they have to combine their designs on a single board where very little space is left for the power converter, which requires “a whole new level of integration and power density for the power designer,” Ronat continues. End users are beginning to understand that they “will need to make some changes from the proven designs and heritage so that they can achieve their new design goals by leveraging new solutions under development by their suppliers.

“The hottest market shift is a huge demand for rad-hard point-of-load converters that can be used in conjunction with traditional isolated rad-hard DC-DC converters to support high efficiency distributed architectures,” says Daniel Sable, president, of VPT Inc. in Everett, Wash. “Using point-of-load converters instead of standard DC-DC converters throughout a system saves size, weight, and dramatically improves efficiency and therefore thermal designs are simplified. All of these are critical issues for spacecraft. This technology is very mature for commercial applications, but there have been few offerings of high efficiency, non-isolated, rad-hard point-of-load DC-DC converters for use in space applications.

VPT offers the hermetically sealed SVGA series of rad-hard point-of-load converters, which steps down voltage at the point of use and is characterized to 100 kilorad total dose radiation, Sable says. The SVGA point-of-load converters are designed and manufactured in a facility qualified to ISO9001 and certified to MIL-PRF-38534 Class H and Class K and MIL-STD-883, he adds.

Challenges in power level and power density also continue to vex radiation-hardened power designers, Ronat says. “As satellite power is increasing, power management with increasing currents becomes more complex. To overcome the weight and power losses of higher current systems, several architecture changes are under consideration or in development such as higher bus voltage and distributed power architecture.

“Higher bus voltages have the potential of reducing power losses by reducing the current,” Ronat continues. “It also has the potential of reducing the weight of the electrical harness. On the other end of the spectrum, digital integrated circuits operate at lower and lower voltages as newer digital technology are introduced into space applications. This is addressed by distributed, multi-stage architecture with an intermediary bus and point of load converters which require new level of controls and performance.

International Rectifier’s M3G RAD-Hard DC-DC Converters are used in space application and the company also offers radiation hardened power MOSFET, diodes, Schottkys, MOSFET driver, voltage regulators, and solid state relays for space and military applications, Ronat says.

Outsourcing die packaging

Rad-hard die designers at Linear Technology in Milpitas, Calif., find that they provide a more cost-effective solution by are outsourcing their packaging needs to hybrid packaging experts such as MS Kennedy, says Rafi Albarian, manager for space and harsh environment products at Linear. In addition to MS Kennedy, Linear also works with Aeroflex in Plainview, N.Y., and Radiation Assured Devices in Colorado Springs, Colo., he adds.

Albarian says outsourcing is the most efficient method with hybrids as they are very complicated designs. In the past companies such as MS Kennedy might buy die from Linear and then integrate the package themselves, he adds.

Now the die manufacturer controls the integration process, which provides more confidence to end-users that the die they are purchasing will be reliable, Albarian continues.

Rad-hard single-board computers

Engineers at Maxwell Technologies in San Diego design single-board computers for space applications in naturally occurring environments, and their users are “looking for moderate total dose performance, high reliability, high processing performance, fast data throughput, a large user memory, and very high resistance to single event upsets,” says Larry Longden, senior director of marketing and technology at Maxwell Technologies. “It takes a long time to reboot a board that has had a non-recoverable upset. Also, with a single processor board the user must wait to find out that an unrecoverable upset has occurred.

In Maxwell’s SCS750 SBC, “every single processor upset is automatically corrected with no user intervention and every non-recoverable upset is detected immediately,” Longden says. In addition, due to our radiation mitigation the probability of a non-recoverable upset is very low, much lower than any single processor system.”

Users get an increased design margin that gives them “the ability to handle growth in system requirements and the natural growth of software as it is developed without changing the design,” Longden adds.

Designers of single-board computers for space are under the same power versus performance pressures that designers of boards for terrestrial applications.

“Today, commercial-off-the-shelf (COTS) rad-hard processor products have settled on the need for higher-performance computing with the ability to support dynamic power reduction, or the scaling back of power during idle and low computing utilization while on-orbit to extend battery life,” Patterson says. “Many applications have determined that the very high single event upset rate offered by less expensive, non-point design COTS products are sufficient for the most demanding high Earth orbit and deep space programs.

“We currently have five products that can support 100 kilorad tolerance with a minor substitution change of components,” he continues. “The near future is our 100 kilorad S960 PowerPC-based 3U CompactPCI single-board computer.”

COTS products also require upscreening at times. “It is encouraged for low cost LEO systems,” Longden says. “The qualification costs to use a plastic part is still very expensive.”

“In general, we're finding that component quality is dropping, therefore upscreening has become an absolute necessity as more device fallouts are found,” Patterson says. “With the addition of counterfeit issues, upscreening or 100 percent component testing of parts has become a service in high demand these days and a natural extension of our value proposition.”

Making it rad-hard

While new products and geometry sizes populate the radiation-hardened electronics world, the methods for radiation-hardening the components remains largely unchanged.

“I think the methods for hardening have not changed,” Maxwell’s Longden says. “For space environments products are developed using a combination of radiation hardened, radiation tolerant, up-screened military and commercial products. Total dose performance is achieved by part selection and shielding. Single event performance is achieved by part selection for latchup and system level mitigation techniques for upsets. For military systems with weapon environments it is still dominated by the use of radiation hardened semiconductors.”

The methods for radiation hardening have not really changed much the last few years as we work down toward smaller form factors, Jordan says. The two methods remain rad-hard by design and rad-hard by process, he adds.

“Radiation hardening needs to be done by process, design, or a combination of both depending on the technology and product so it is a very specialized and complicated development process that is mastered only by a few companies,” Ronat says. “Improved design tools and manufacturing process control are making product development easier and faster, but significant challenges remain as the manufacturing of these products and ensuring reliability continues to require significant testing and exacting controls.”

“Radiation hardened by process is still the only demonstrated method for achieving the full range of radiation hardened program requirements,” Nootbaar says. “Honeywell would anticipate hardening by process to continue to be the method at least through 90 nanometer development. Programs continue to adapting commercial technologies using redundancy at the circuit and chip level.

“Beyond 90 nanometers, where the cost of capitalizing a 65 nanometer wafer fab or smaller is extremely high compared to earlier geometries, radiation hardening by design such as triple redundancy voting will most likely be the most accepted method,” Nootbaar says. “This will not provide the strategic hardness that is required by some applications, and therefore 90 nanometer and 150 nanometer radiation hardened by process will continue to be utilized for these critical applications. In addition, radiation hardened by design will lose some of the geometry benefits with respect to power and density due to the redundancy and will effectively be equivalent to one generation earlier technology.”

For example, 65 nanometer radiation hardened by design would be equivalent to 90 nanometer radiation hardened by process for power and density, he continues. “Therefore, it is believed that the next generation technology beyond 90 nanometer would be radiation hardened by design at the 45 nanometer process node.

“The process for radiation-hardening of DC-DC converters consists of a combination of component selection, circuit worst case analysis, and radiation testing at both the component and converter level to verify the required performance when exposed to the space environmental conditions,” VPT’s Sable says. “A strict, well defined test plan is paramount to the success of the product development plan.

“The radiation hardness verification consists of determining parameter degradations through piece part radiation testing and applying them to the circuit analysis, Sable says. “The final converter design is then radiation tested to ensure that the converter parameter degradations can be explained by the component level degradations. For example, the impact of the shift in input offset voltage and current of an operational amplifier used in the current limit circuit should show up as a predictable shift in output current limit in the converter over radiation. It is also important that measurements are made at several radiation levels during the component level and converter level tests because some parameter degradations are not monotonic and therefore may not be worst case at the design radiation level.

“The design of enhanced low dose rate sensitivity (ELDRS) free converters can require long test cycles due to the fact that the time to reach the test dose level can be several months,” Sable notes. “This has increased both cost and schedule for product development for space products, however its value to the long term reliability of the mission is critical.”

Development times are longer not only because of the radiation-hardening aspect especially with FPGAs, Aitech’s Patterson says.

“The development time is actually taking longer because of the additional features that now must be built in the FPGA design as the development of the FPGA code is becoming more complicated,” he says. “This is due in part to having more FPGA gates and more features which are being added. Many times, deliveries can be shortened as Aitech has refined our manufacturing process and tailored it to be able to respond to small and large quantity orders simultaneously.”

Enhanced low dose rate sensitivity (ELDRS)

“A major industry concern the past few years has been enhanced low dose rate sensitivity (ELDRS), says Leonard Leslie, manager, space programs at VPT. Designs must not show ELDRS, which is “caused by components degrading earlier when exposed to a dose rate closer to that seen in the application, as opposed to the high dose rates traditionally used for design qualification,” he adds.

The high dose rates of greater than 50 rads per second “used for testing rad-hard devices historically may be a flawed method for many of the user’s applications,” Leslie notes. “A low dose rate of less than 10 megarads per second may provide a more reliable predictor of actual tolerance in many applications.

“Some extreme reliability applications VPT supports for the U.S. government, such as the GPS III program, also need custom designs that have enhanced requirements in addition to total ionizing dose and single event upset tolerance, he says. “These requirements include increased component screening and hardening for special environments that may be far in excess of even the typical stringent space component levels.

Next-generation technology

“Work is continuing on next generation technologies for future radiation hardened electronics,” Honeywell’s Nootbaar says. “There is strong support and interest in carbon nanotube technology for high density, low power non-volatile memories and logic. Carbon nanotube conductive fabric provides a means to implement a very low power molecular switch that requires no stand-by power to maintain. It is inherently radiation hard providing optimism for the next generation technology and applications.

“Inherent hardness improved in commercial technologies over past several generations as oxide volumes decreased reducing total dose effects,” he continues. “Going forward, this trend may reverse as single event effects become more prevalent in smaller commercial technologies.”

Rad-hard company information

Actel, Mountain View, Calif. 650-318-4200 www.actel.com

Aeroflex, Colorado Springs, Co. 719-594-8000 www.aeroflex.com/ams

Aitech, Chatsworth, Calif. 818-700-2000 www.rugged.com

ASIC Advantage, Sunnyvale, Calif. 408-541-8686 www.asicadvantage.com

Atmel, San Jose, Calif. 408-441-0311 www.atmel.com

BAE Systems, Manassas, Va. 703-361-1471 www.baesystems.com

C-MAC Micro Technology, Buckinghamshire, United Kingdom 44 1628 859 680 www.cmac.com

Crane Interpoint, Redmond, Wash. 425-882-3100 www.interpoint.com

Harris Corp., Melbourne, Fla. 800-4-HARRIS www.govcomm.harris.com

Honeywell, Plymouth, Minn. 612-951-1000 www.honeywell.com

International Rectifier, El Segundo, Calif. 310-726-8000 www.irf.com

Intersil Corp., Milpitas, Calif. 408-432-8888 www.intersil.com

Linear Technology Corp., Milpitas, Calif. 408-432-1900 www.linear.com

Maxwell Technologies, San Diego, Calif. 877-511-4324 www.maxwell.com

Microelectronics Research Development Corp., Colorado Springs, Colo. 719-531-0805 www.micro-rdc.com

Micropac Industries, Garland, Texas 972-272-3571 www.micropac.com

Modular Devices, Shirley, N.Y. 631-345-3100 www.mdipower.com

MS Kennedy, Liverpool, N.Y. 315-701-6751 www.mskennedy.com

Peregrine Semiconductor Corp., San Diego, Calif. 858-731-9400 www.psemi.com

Radiation Assured Devices, Colorado Springs, Colo. 731-531-0800 http://radiationassureddevices.com

Semicoa, Costa Mesa, Calif. 714-979-1900 www.semicoa.com

STMicroelectronics, Geneva, Switzerland 41 22 929 29 29 www.st.com

Synova, Melbourne, Fla. 321-728-8889 www.synova.com

Teledyne Microelectronic Technologies, Los Angeles, Calif. 310-822-8229 www.teledynemicro.com

3D-Plus, McKinney, Texas 214-733-8505 www.3d-plus.com

Triad Semiconductor, Winston-Salem, N.C. 336-774-2150 www.triadsemi.com

Ultra Communications, Vista, Calif. 760-652-0011 www.ultracomm-inc.com

VPT, Everett, Wash. 425-353-3010 www.vpt-inc.com

Xilinx, San Jose, Calif. 408-559-7778 www.xilinx.com

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