GSWP300W-EVBPA
GaN E-HEMT Wireless Power Transfer Evaluation Board
Technical Manual
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GSWP300W-EVBPA Rev 220215
© 2022 GaN Systems Inc.
www.gansystems.com 21
Please refer to the Evaluation Board/Kit Important Notice on page 27
The
PA’s
system reliability is optimized when the temperature rise of each device is kept to a minimum,
including that of the GaN E-HEMTs. The GS66508Bs are especially well suited in this regard, for a
number of reasons. First, they have very low switching losses which allows them to operate at high
efficiency and a low temperature rise at 6.78MHz, the common frequency used for resonant wireless
power transfer. Secondly, the bottom-side cooled GaN
PX
® packaging provides an extremely low
thermal impedance for efficient heat transfer to the heatsink, thereby drawing heat out of the device.
This GaN based design is able to operate over a wide ambient temperature and with convection cooling,
eliminating the need for cooling fans. These advantages support a PA design with excellent thermal
performance up to 300W output power.
The temperature plot of the PA design was measured and captured with a SEEK thermal camera and is
shown in Figure 20.
The hottest devices are the first inductors, with the hottest inductor recording 35˚C
above ambient. The temperature rise of the GaN E-
HEMTs, by comparison, is only 3˚C. Because the
GaN E-HEMTs run very cool, this allows operation over a very wide temperature range and extends
operation to a higher power level while simultaneously simplifying the cooling system design and
reducing the cost.
Figure 20 •
Thermal measurement of PA without EMI filter at 300W output power
