EPC Space Unveils New 40 V Rad-Hard GaN Power Transistor

Looking to further its reach in the rad-hard market, EPC Space last Thursday released the EPC7091G, a high electron mobility transistor (HEMT) that it says both costs less and outperforms any comparable rad-hard silicon MOSFET. 

The move comes just weeks after EPC, which runs EPC Space in a joint venture with VPT, Inc., made similar claims upon the release of its latest 350 V GaN transistor, which the company says is 20 times smaller than comparable silicon offerings and, of course, cheaper.

 

The EPC7091G. Image [modified] used courtesy of EPC Space

 

Here, EPC Space is no less ambitious. Per CEO Bel Lazar, the fresh EPC7019G features the lowest on-resistance of any packaged rad-hard transistor on the market, providing it with what he calls “superior figure of merit.” 

An eGaN FET, the EPC7019G has a total dose rating greater than 1 Mrad and SEE immunity for LET of 85 MeV/(mg/cm²). The unit can handle 49 A continuously, as well as manage a single 300 µs drain current pulse of 530 A. It is is available in a compact, hermetic package with dual gate in a footprint measuring less than 45 mm². Chip-scale versions of the device are also available. 

 

The Advantages of Gallium Nitride 

GaN-based devices, when compared to last-generation silicon, feature higher breakdown strength, lower gate charge, lower switching losses, better thermal conductivity, and lower on-resistance. 

These vital factors enable GaN power devices to operate with higher switching frequencies, which translates to smaller and lighter filtering components. The result is greater power density and efficiency, and more compact, lighter circuitry—factors critical for spaceborne missions.

 

Standout Features of the EPC7019G

• QRR reverse recovery charge (QRR): 0 nC
• Total gate charge (QG): 22 nC (max)
• Gate drain charge (QGD): 3.4 nC (max)
• Thermal resistance between the junction to the case surface (RϴJC ): 2.25 °C/W

 

Other Specifications

VGS range is from +6 to -4 V, though EPC Space recommends use at no greater than 5 V, as the eGaN is fully conducting at that point.

 

Dynamic Characteristics

Capacitive Characteristics:

• Input capacitance (CISS): 2830 pF
• Reverse transfer capacitance (CRSS): 35 pF
• Output capacitance (COSS): 1660 pF
• Effective output capacitance, energy-related: 2130 pF
• Effective output capacitance, time-related: 2540 pF

Charge Characteristics:

• Gate-to-source charge (QGS): 9.1 nC
• Gate-to-drain Charge (QGD): 3.4 nC 
• Output charge (QOSS): 51 nC 
• Source-to-drain recovery charge (QRR): 0 nC

 

Radiation Characteristics

• The EPC7019G is tested according to MIL-STD-750 Method 1019 for total ionizing dose validation. 
• Total radiation dose: rated to 1000 krad
• Single event (SEE) immunity (with VDS of up to 100% of rated breakdown): Linear energy transfer (LET) of 85 MeV/mg/cm2
   
• Maintains Pre-Rad specification at: 
  - A low dose radiation rate of 100 mRad/sec
  - Up to 3 x 10^15 Neutrons/cm2

 

Applications

• Power supplies in: 
  - Satellites
  - Space mission equipment
   
• Motor drives for:
  - Robotics
  - Instrumentation
  - Reaction wheels
  - Deep space probes
   
• Nuclear facilities

 

Physical Considerations

Operating temperature range is -55 to +150 ℃

 

Availability

Earlier this year, EPC Space announced it had inked a deal with Digi-Key for the global distribution of its entire line of rad-hard GaN-on-silicon (silicon substrate) transistors. The agreement also covers the company’s family of rad hard enhancement mode GaN (eGaN) drivers and power stages. 

 

Digi-Key is distributing EPC Space's entire line of rad-hard GaN transistors. Image used courtesy of NASA/Unsplash

 

Though EPC Space directs customers to contact its factory directly for inquiries regarding availability and delivery of the EPC7091G, it’s presumable the product will eventually be made available via the distribution giant. 

Feature inage used courtesy of NASA/Unsplash