EPC Space Announces a Family of Radiation-Hardened 40V to 300V GaN Power TransistorsOctober 08, 2020 by Gary Elinoff
The new enhancement-mode Gallium Nitride (eGaN) devices are aimed at critical applications in defense and aerospace
Gallium Nitride based power semiconductors are now rapidly replacing last-generation silicon-based MOSFETs on Earth, and new radiation-hardened versions are extending the change to space-based applications as well.
Image courtesy of EPC Space
The members of EPC Space’s family of eGaN power switching high-electron-mobility transistors (HEMT) feature drain currents ranging from 4 to 30 amps. These devices enjoy significant advantages over last-generation silicon-based MOSFETs.
What Makes Space Qualified Power Transistors Different?
Once a vehicle destined for space leaves the Earth’s protective shell, it is exposed to intense radiation that would quickly degrade an ordinary semiconductor. Semiconductor devices that are Rad Hard, or radiation-hardened, have been specially designed to withstand this serious hazard.
This is advantageous in any case, even for the easily replaceable swarms of CubeSats now populating low earth orbit (LEO).
It's more important still for deep space missions, which will require space vehicles to suffer exposure to huge doses of radiation during the course of their long interplanetary journeys. If they were to employ non-radiation hardened transistors, there would be a requirement for bulky shielding that would add weight and take up space, and, in effect, limit the effective payload of the system.
What is Radiation Hardened?
Members of the new family of space-hardened devices can withstand a total radiation dose of up to 300 kRAD.
Single event effect (SEE) immunity for high-linear energy transfer (LET) is 83.7 MeV/mg/cm2
The units maintain their pre-radiation specifications at a low dose radiation rate of 100 mRad/sec.
Under neutron bombardment of up to 1013 neutrons/cm2, the devices will also maintain their radiation specifications.
The new GaN-based power semiconductors, as a result of their lateral die structure, all feature very low gate charges (QG). This enables extremely fast switching speeds, which in turn results in higher power densities, higher efficiencies, and more compact packaging, all highly critical in space-based applications. In addition, EPC Space’s new devices feature very low RDS(on) values, resulting in less wasted power.
The units can also sustain an 80 µS single pulse of the drain current of from three to four times the continuous rated value. A summary of the principal electrical parameters of the seven-member family is presented below.
The seven members of the new family of space-hardened power transistors. Table courtesy of EPC Space
All members can operate over a temperature range of -55 to +150℃
“EPC Space is excited to bring the tremendous performance and reliability of GaN technology to the markets of defense and aerospace,” said Bel Lazar, CEO. “We are able to offer designers a superior technology with significant space heritage as thousands of our Rad Hard GaN devices have been in orbit since January of 2019.”
Size and Weight Are Critical
Important considerations even in the most mundane earthly applications, are of vital concern in space. The transistors take up from between 11.8 and 22.2 mm2. Weights are from 0.068 and 0.135 grams.
Spaceborne applications that will benefit from the new series of Rad-Hard transistors include:
- Commercial satellites
- The lidar systems employed in space-based docking, navigation, and robotics
- Power supplies for satellites
- Driving and controlling the electric motors used in space-based applications
- Ion-thrusters employed in satellite orientation and deep-space propulsion