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STMicroelectronics Rad-Hard ICs Target ‘New Space’

Built with low–earth orbit (LEO) in mind, STMicroelectronics’ latest series of radiation–hardened ICs boast a plastic package with a total ionization dose immunity up to 50 krad(Si), enabling next–gen satellites to provide earth observation and broadband internet from the relative safety of LEOs. Hello new space, goodbye old space.

ST’s newest LEO series includes a data converter, a voltage regulator, an LVDS transceiver, a line driver, and five logic gates. They possess high immunity to total non–ionizing dose and single event latch-up immunity up to 62.5MeV.cm²/mg, can withstand temperatures between –40 to 125 degrees Celsius, and are based on AEC-Q100 specifications — all which ST claims will enable them to meet the rising demand to deploy additional satellite constellations thanks to both their low-cost plastics packaging and the allure of what new space can offer.

But what exactly do we mean by “old space” and “new space”? ST’s senior marketing manager for Space and Hi–rel products, Thibault Brunet, explained the distinction here comes down to the amount of particle radiation within geostationary earth orbit (traditional space) versus LEO (new space).

“Space is not homogenous. Traditional space is mostly geostationary orbit. Here, you have a lot of high energy particles, so a product has to be very robust. New space is low orbit, where there are much less particles because it is already protected by the atmosphere. It’s a complete change of dimension,” Thibault said.

Because LEO provides both Magnetic Field protection and atmospheric protection — Magnetic Field protection being the stronger of the two, an ST spokesman subsequently pointed out — it offers more leeway in terms of the type of packaging used in producing ICs for space. Unlike new space, traditional space requires hermetically sealed ceramic packages capable of withstanding the elevated levels of radiation found in higher geostationary orbits. With a lack of high energy particles in new space, plastics packaging then becomes a feasible option.

“This new series we are releasing, we are taking advantage of 40 years’ experience in space hardened products. On one hand, we are taking advantage of our expertise in automotive products as well as our quality scheme in plastic parts and we are putting them together to make products that have radiation immunity toward particles that exist within low orbit,” Thibault said.

While not as robust, plastics packaging can also be produced in much larger volumes compared to traditional ceramics packaging, making them relatively low cost.

“The price of radiation hardening in traditional space is high because the quantities are low. In our industry, what affects the price is not so much the package, not so much the particular task that we are doing. It’s that everything is a bit specific, and a bit more expensive, but ultimately it’s because there is low volume. This is what makes the price very high,” Thibault said.

Additionally, hermetic ceramic packaging must pass stringent QML or ESCC qualifications and production processes, which adds to its higher costs. That is not to say, however, that ST’s rad–hardened, plastic packaged ICs are any less qualified for orbit into space.

“The required performance and quality assurance for LEO satellites are similar to those for traditional satellites, and are designed with optimized qualification and production flows and economies of scale,” ST said in its press release. “They require no additional qualification or up-screening from their users, and therefore eliminate significant cost and risk.”

For ST, this includes implementing external terminations’ finishing to ensure metal fatigue, as evidenced by unique “whiskers”, doesn’t occur.

“Old space demands ceramic, hermetic packages while new space is perfectly comfortable with plastic packages as long as we are able to demonstrate that there are no whiskers. In space there is no gravity, and when there is no gravity, you have a higher probability of producing whiskers, which create short circuits that can completely destroy the device,” Thibault said. “We have ways of simulating life–testing devices that allow us to test and extrapolate how the device will perform over five years without actually having to test it for five.”

“There’s the packaging and screening, which can be challenging, but we’re lucky at ST that we invested $30 million recently to completely upgrade our facility, so we have state–of–the–art equipment, capacity and we have grown in terms of capabilities, so we are now touching a much more advanced market.”