From the AIM satellite to Surface Rover spacecraft, high-tech microelectronic circuitry is at the heart of aerospace technology, and must be heavily protected against cosmic radiation. Yet there’s a threat to micro circuitry back here on Earth as well – and it’s giving FPGA designers some serious headaches.
When engineers create complex electronic systems, the reliability of the semiconductors and Field Programmable Gate Array (FPGA) designs is paramount. In deep space, radiation is a major hazard which must be factored in the mechanical design of the spacecraft. However, as natural background radiation (NBR) it can pose a threat to terrestrial applications too. PCB designers must choose their microprocessor components carefully, ensuring they can withstand fluctuations in natural radiation levels, to maximize system reliability. But what if those levels stop being in the background?
NBR originates from a number of sources, including radioactive decay of natural and man-made materials; cosmic rays from distant stars, and a constant stream of charged particles originating from our own sun – the solar wind. Most of these particles are deflected into the magnetosphere. However, others penetrate the atmosphere, creating high energy neutron showers which eventually reach the Earth’s surface – causing chaos and failure in electronic systems by interacting with semiconductors and FPGA chips.
High levels of sunspot activity equate to higher incidences of electronic failure. The neutron flux value is an important indicator of sunspot levels, which follow an 11-year cycle of activity. Or at least, they did. The current cycle has been strange, to say the least, leading many observers to speculate that the 2012 Mayan Prophecy may arrive in the form of a massive Solar Storm – against which the Earth’s magnetosphere will be largely ineffectual. The most famous event was in 1859. To give you an idea of its potential effects on electronic systems today, telegraph systems burst into flames, or sent “ghost” messages after being disconnected. Operators were electrocuted and pylons erupted in showers of sparks. The Northern Lights were seen as far south as the Caribbean.
The event, known as the Carrington Superstorm after the London astronomer who documented it, was the most powerful solar storm in recorded history – and due a recurrence. There was, in fact, a scare recently, on Valentine’s Day 2011. Although minor compared to the 1859 event, it nonetheless overwhelmed the NASA Solar Dynamics Observatory satellite, albeit momentarily.
Neutron flux density varies with the Earth’s magnetic field, but levels overall have been rising steadily over the last 45 years. Shielding of circuits is not practical – neutrons can penetrate several feet of concrete – so FPGA designers are seriously concerned. Another problem is alpha particle contamination. The plastic moldings used in semiconductor packaging emit alpha particles, which unavoidably interact with the components, exacerbating the neutron flux problem.
There is an increasing need for reliability in terrestrial hardware systems. It is essential for PCB designers to be aware of the threat of rising NF levels on commonly used FPGA devices, and minimize risk of system failure by choosing FPGA designs with proven immunity.We at Enventure Technologies are specialists in the field of FPGA design, and can offer all the support you need in developing your product – whatever 2012 brings.