Microchip and EPC Combat Radiation With New Rad-hard FETs
Technology for space applications has been an important part of 2021, thus more components are coming out that are rad-hard. Recently, two new FETS have come out, what do they bring to this space?
Designing electronics is complex, but designing them to operate in space is even more complicated. Far beyond the protective veil of our earth’s atmosphere, the effects of ionizing radiation become non-negligible and can have harmful effects on electronics and their operation.
High-level example of types of radiation and its penetration Image used courtesy of Tempo Automation
For this reason, space electronics often require radiation-hardened, or rad-hard, components that take special manufacturing and design measures to shield from the impact of space radiation.
This month alone has seen a variety of new rad-hard devices reach the market. This article will look at two new rad-hard FET offerings to see how the industry enables space-bound electronics.
The Need for Rad-Hard Electronics
Outside of our atmosphere's protective cloaking, many other ionizing radiations that electronics on earth are not typically exposed to in the depths of space are not typically exposed to.
Due to the ionizing nature of space radiation, that radiation can often affect devices by generating a charge inside silicon-based electronics.
Effect of ionizing radiation on silicon electronics. Image used courtesy of Windows to the Universe
This charge build-up can often disrupt the crystalline nature of an electronic component, thus causing a complete change or even the failure of the operational characteristics of the device. As the electronic components are exposed to more radiation, the function is degraded and then fails.
Another factor is the effect of cosmic rays on electronics. Cosmic rays can also change digital states, which could lead to bit-flip errors and erroneous data. This radiation effect worsens as electronics get smaller, thus becoming more susceptible to the effects of a low-energy interferer.
Since there are many challenges in designing electronic components for space, it is always interesting to see companies coming out with more rad-hard technology.
Microchip’s Rad-hard MOSFET
The first rad-hard offering to look into is a new power MOSFET from Microchip.
Microchip's newest rad-hard MOSFET, the M6 MRH25N12U3. Image used courtesy of Microchip
Aimed specifically at power supply design for space applications, the new M6 MRH25N12U3 rad-hard MOSFET is a 250V, 0.21 Ohm Rds(on), silicon-based offering. Microchip says that its new FET could be useful as the primary switching element in conversion circuits, SMPS, motor drivers, and general switching applications.
In terms of rad-hard operation, it states that the device is rated to withstand a total ionizing dose (TID) up to 100 krad and single event effects (SEE) with linear energy transfer (LET) up to 87 MeV/mg/cm2.
Though it may not seem empirically like an ordeal, power design in general, space applications can be an even more difficult challenge. With this in mind, it could be beneficial to look into alternative materials that could help with both the power and radiation hurdles.
One material that is expanding its uses here on Earth but is starting to look towards space is GaN.
EPC’s Rad-Hard GaN FET
It seems the rise of GaN over Silicon has now found its way to space, as EPC recently announced its newest rad-hard GaN offering.
EPC's newest GaN FET, the EPC7014. Image used courtesy of EPC
The new EPC7014 is a 60 V, .340 Ohm, rad-hard GaN FET. This FET is the first of a family of rad-hard transistors from EPC.
This family claims to offer a stable temperature operating range of -55 to 150 C and a 0.81 mm2 footprint. The EPC7014 is designed for commercial satellites, deep-space probes, and space power supply circuitry.
Interestingly, GaN devices seem to offer an inherent radiation immunity due to their device physics and layout. The EPC7014 is rated for TID greater than 1 Mrad, and a SEE immunity for LET of 85 MeV/(mg/cm2).
The utilization of GaN could potentially open even more doors for space-rated components.
Powering Space Electronics
Human exploration and space utilization require specialized electronic equipment that accounts for variables that do not exist here on Earth. Both the offerings from Microchip and EPC offer an impressive combination of power efficiency and radiation tolerance––a must for space power electronics.
Since designers are searching for other materials and electronics to help balance radiation and power in space, more and more potential solutions and components are sure to present themselves.