Cree's GaN HEMTs tempt telecoms firms
Claiming HEMT efficiency beyond that of its industry rivals, GaN-on-SiC pioneer Cree says its latest microwave transistors are grabbing the attention of all the relevant major base station manufacturers.
The company announced it had released the first samples of two 120 W devices from its Durham, North Carolina production lines on January 29.
Jim Milligan, Cree s director of RF and microwave components, told compoundsemiconductor.net that production will now expand over the next year as the performance of the HEMTs continues to win customers over.
“Cree transistors typically have higher gain, efficiency and bandwidth capability as well as being more highly correctable for linearity under digital pre-distortion compared to competing GaN solutions we are aware of,” he said. “Our SiC substrate provides a thermal performance advantage over GaN-on-silicon products.”
The HEMTs target high-capacity wireless networks, including 3G wideband CDMA systems, WiMAX and LTE, but are not limited to these applications.
The CGH21120F is designed for the 1800-2300 MHz frequency range and while the CGH25120F is designed for 2300 and 2700 MHz.
When operated at 28 V, the lower frequency device boasts 70 percent efficiency and provides gain of 16 dB while delivering 110 W of peak continuous-wave power.
Two CGH21120F transistors have also been combined in a W-CDMA Doherty amplifier configuration, where they generated 80 watts of average power with a record 52 percent efficiency.
Milligan points out that production of GaN HEMTs is set to benefit from the core GaN and SiC material expertise that comes from Cree s high-volume LED manufacturing.
“The microwave, power and LED businesses complement each other in terms of economies of scale and technical expertise,” he said.
These transistors maintain Cree s tradition of breaking GaN amplifier efficiency records and bring the company s second such announcement in this frequency range in a year.
The first was announced at the IEEE Microwave Theory and Techniques Society s International Microwave symposium in June 2008, where a number of other GaN performance records were broken.
In October Cree s GaN rival Fujitsu continued the efficiency-record breaking party. Two of the Japanese company's GaN HEMTs combined to produce 320 watts of power at 57 percent efficiency in the C-band region between 4 and 8 GHz.
Meanwhile, Cree announced on January 22 that it will sell its GaN HEMTs to a broader market than just system makers, under its partnership with distributor Digi-Key.
