The commercial off-the-shelf (COTS) electronics initiative of the mid-1990s occurred for two key reasons. First, acquiring customized components that could withstand harsh military environments came at a cost premium. Second, highly desirable leading-edge technologies, driven by larger market forces, were being developed for commercial applications. For these reasons, the U.S. government mandated that military contractors begin using a COTS approach, not only to reduce costs, but also to take advantage of emerging technologies.
COTS is based on the premise that military electronics programs could adopt or adapt commercially available components, boards, and systems, taking advantage of technological and economic benefits of commercial products. While COTS has been largely successful (the stories of $500 coffee pots and $5,000 toilets are long past), there is still clearly room to improve the way that commercial components meet the military’s needs for reliable service in extremely demanding operational environments. Harsh environments typically require operational specifications supporting temperature ranges (from -55°C to +125°C), high altitude, high and low humidity, extreme vibration and shock, and potentially corrosive conditions.
Where Programmable Logic Fits
Military applications for programmable logic devices (PLDs) are vast. They encompass ground, airborne, mobile, and naval radars, as well as secure communications. These applications involve end-deliverables such as field sensors, hand-held and portable radios, military GPS, military radios, and secure wireline. In addition, PLDs are ideal in computing applications including avionics and processing systems, and single board computers, including guidance and control systems for missiles, smart munitions, and unmanned aerial vehicles. Add to this list electronic warfare, countermeasures, identification-friend-or-foe (IFF) systems, radar jammers, and infrared detectors. There are even more.
The challenge the U.S. military is facing is acquiring military-grade PLDs from an industry whose main emphasis is decidedly not military applications. In fact, military applications comprise less than 1 percent of semiconductor sales in North America. Consequently, the military does not have a lot of leverage to demand PLD vendors to address its specific needs. These needs include eliminating the risk of devices failing or underperforming in the harsh operating environments discussed (which highlights reliability and productivity concerns), security and lifecycle questions, and overall access to technology that maintains operational advantages over potential opponents.
The challenges facing typical PLD vendors who are attempting to address the COTS military market include anti-tampering concerns; “single event effects,” when devices malfunction in high altitude applications; the aforementioned quality and reliability issues; limited intellectual property (IP) cores for data processing and temperature support requirements; limited raw die supply for multi-chip module integration; and supplier business models that do not support military applications. One element of device reliability is packaging: the commercial market is moving toward environmentally friendly unleaded packaging, which can adversely affect reliability in strenuous military applications. Also, end-of-life (EOL) solutions are needed for military applications that require 10-plus years of product use; the shelf life of most commercial devices is only about 2 to 3 years.
Bottom line, the military needs an improved COTS solution. What’s needed now is a multi-pronged approach, addressing specific military applications featuring:
- a reliable supply chain
- state-of-the-art packaging
- device offerings for multiple military market segments
- military temperature support
- die business support
- timely product EOL notifications
- obsolescence protection
- anti-tampering design security
The Aerospace Qualified Electronics Components (AQEC) working group has produced the GEIA-STD-0002-01 standard, shortly due for release. This standard addresses many military concerns for COTS electronics. PLD vendors must apply the GEIA standard as part of an “enhanced COTS” approach. An enhanced COTS approach gives the aerospace industry access to COTS products at an acceptable cost while addressing the added requirements listed above.
Key to success is providing the military with a steady stream of devices via a reliable supply chain. Also needed is military-grade packaging. This is a two-fold process. With today’s leading-edge process technologies, packaging should be developed in parallel with the device itself to ensure reliability and compatibility to the dice. Next, unleaded packaging can affect device reliability, so both leaded and unleaded PLD packaging options are essential.
Custom Solutions for Unique Military Challenges
Because there are divergent product requirements for each military market segment, it is virtually impossible to supply the entire market with a single product. A COTS supplier can cater to one specific market segment with a single product offering. However, what’s desired by DoD contractors is a range of PLDs meeting the requirements for a range of market applications. The mix should include high-density, high-performance devices, as well as low-cost, low-power devices. Combining varying device types with a structured ASIC manufacturing path from design-to-production process reinforces the value this market segment requires. Using structured ASIC devices for production volumes can add another level of COTS robustness with lower cost, low power, security to mitigate against tampering, and increased performance.
PLDs Fit Military Designs
Radar systems provide position and velocity of objects with respect to the radar unit. In some advanced systems it is possible to determine the shape of the object. The military requires all-weather, day-and-night imaging sensors to supply reconnaissance, surveillance, and targeting information. Radar systems demand tremendous amounts of digital signal processing (DSP) power supplied by PLDs, especially when used for target tracking and designation purposes.
Current efforts bring the processing closer to the antenna where pre-processing and high-speed on-chip processing of chip data signal is required. Implementing both on a single device could increase the risk of device failure in development. Partitioning tasks in two different devices ensures lower risk for thermal dissipation and flexibility. An enhanced COTS strategy provides the military with devices featuring DSP capabilities plus devices with high-speed I/Os capable of 6 Gbps (gigabits per second).
In electronic warfare, the military must suppress enemy air defenses to be able to accomplish war objectives and survive. To achieve this, the military uses specialized aircraft designed to neutralize, destroy, or temporarily degrade enemy air defense systems through either physical attack or electronic warfare. Specialized aircraft use electronic warfare devices, called jammers, to temporarily suppress enemy air defenses by transmitting electronic signals that disrupt enemy radar and communications. Other specialized aircraft use anti-radiation missiles that hone in on radar used by surface-to-air missiles and anti-aircraft artillery systems to physically degrade or destroy them. Altera ® devices are used in these specialized aircraft to provide considerable processing power in demanding conditions.
Leading-edge PLDs are manufactured in 90-nm process technologies and include productivity tools, ensuring schedules are met. A methodology of reuse also ensures that previously developed military algorithms can be effectively used again, resulting in significant cost savings.
Enhancing COTS expands the industrial grade temperature range from -40C down to -55C at the low end, and from 100C to 125C at the high end. This is the required range for military grade devices. PLD devices for military and aerospace must operate in high-altitude and high-temperature environments. The long product life cycles of military products demand a consistent supply of die for integration into multi-chip modules for important space, weight, and power savings as well as engagement in multiple die opportunities with partners.
Since supplying the military with reliable PLDs is critical to ensuring military systems readiness, it is imperative for PLD vendors to provide timely product change notifications. Minor device changes, such as die revisions and packaging composition that could affect board timing and reliability, could have a major adverse impact in the field due to the extreme operating climates. Suppliers going beyond standard COTS requirements should post all company product change notices on their website, and product discontinuance notices should alert military customers long in advance to avoid any disruption of product supplies.
End-of-Life (EOL) management in an enhanced COTS approach employs a commitment to product availability over time. Some vendors offer long-term availability, only with revenue commitments and a large supply build program. An alternative,is a large single production run with inventory management, and third-party vendor relationships to ensure a continued, uninterrupted product supply. An inherent benefit of PLDs is that they can be used in a variety of vertical market applications, which minimizes obsolescence concerns.
Finally, anti-tampering concerns and protection of IP are obviously critical to design security, especially for military system applications that are exposed to enemy forces or exported to allies. Features that address these concerns, such as 128-bit Advanced Encryption Standard (AES) algorithm, FIPS-197 compliance, and key storage on-chip non-volatile location, are found on some PLDs. These capabilities encrypt military IP that is programmed into the FPGA and mitigates IP modification in the device. Many COTS solutions do not take into account security that is not volatile.
The COTS initiative has largely met its mandate, but there’s more to be done. Providing devices that enable systems readiness and are based on leading-edge technologies at reduced costs is critical to U.S. military success. There is room for improvement in how commercial products perform in demanding military operational environments. In response to this dilemma, PLD vendors and others need to adopt an “enhanced COTS” approach that supplies the military with reliable, risk-averse devices that address all of today’s technical and business requirements. Going beyond COTS is the way forward.