Satellites typically have long missions (15 to 20 years) and span a wide range of orbits, including geosynchronous Earth orbit (GEO) and deep spaceflight. These large vehicles in deep space have high radiation level requirements and must meet stringent reliability and quality demands so that electronic integrated circuits (ICs) aren't impacted by radiation. With the development of small-satellite constellations that bring broadband Internet access to every corner of the world, there is concern about the length of time these small-satellite constellations can endure the radiation they are subjected to in low Earth orbit (LEO).
These LEO small-satellite constellations—positioned below the Van Allen radiation belt, where most of the destructive particles are trapped—have low radiation and less stringent reliability and quality requirements than their large cousins, according to a new white paper from Intersil Corp. (Milpitas, CA), a Renesas Company. The paper explains how satellite makers are addressing market demands—GEO versus LEO small-satellite constellations—and compares new radiation-tolerant plastic ICs with the commercial off-the-shelf “radiation hardened” ICs that are widely available today.
Companies supporting small-satellite technology are working to navigate the fragmented GEO versus LEO market and develop ways to “engage without dramatically changing their business model.” There also needs to be industry specifications or quality standards to address the small-satellite supplier base, said Intersil’s paper.
“Seeing this emerging need and convergence of requirements for larger satellite constellations in higher LEO altitudes sparked Intersil to engage its customer base. Through in-depth engagements, Intersil has created a cost-effective, radiation-tolerant product development and manufacturing flow to address these emerging small-satellite needs. The result is a new family of products that are being released in small-form-factor, surface-mount plastic packages, typically with nickel/palladium/gold (Ni/Pd/Au) lead finishes,” said Intersil’s paper.
These ICs will have one-time characterization during development and undergo harsher testing including a military temperature range of -55° to 125°C. “The parts will also be qualified on an AEC-Q100-like basis with up to 2,000 hours of burn-in testing, exposure to 500 temperature cycles and package moisture sensitivity testing. This is a significantly different development and manufacturing flow compared with traditional radiation-hardened products, which have large ceramic packages, radiation assurance testing in the product screening flow, and temperature and burn-in testing on each part in production, all of which drives up the IC cost.”
For large constellations of small satellites in LEO, a single event effect (SEE) occurring would likely be lower than in GEO, but “is still of concern” for these satellites “at an altitude close to or getting into the Van Allen Belt. For heavy digital content ICs, like a microprocessor, an SEE is typically not a catastrophic event. However, when it comes to the device that is powering the microprocessor or processing sensor data signals to the microprocessor, this could be a different story.”
If a satellite’s power device or “operational amplifier are impacted from a heavy ion or particle in such a way that its output is disturbed to unacceptable levels in a transient event, these devices can potentially damage or destroy the device connected to the output, like a microprocessor,” which could mean total “mission failure” for the entire satellite.
Intersil is launching three initial radiation-tolerant, plastic packaged ICs, which will help reduce the size, weight and power of small satellites. “These parts combine commercial-like performance, reliable packages and the radiation performance needed for satellite constellation programs that are cost effective and dramatically minimize program risks,” said Intersil.
In addition to large satellite constellation programs, these products are also suitable for other applications such as launch vehicles, medical equipment, high altitude avionics (aircraft electronics) and nuclear power plants.