Fujitsu smashes GaN HEMT power record
Japan-based Fujitsu Laboratories has developed a GaN HEMT amplifier that emits 174W at 63V.
The power output is a world best and the device also features a record drain efficiency of 40%. Fujitsu says that the figures fulfill W-CDMA requirements for 3G wireless base stations.
“This [breakthrough] overcomes the technical hurdle for output needs exceeding 150W required for realistic application in 3G mobile systems,” said the company.
Currently researching mass-production techniques and testing reliabilty, Fujitsu expects to have commercial GaN HEMT amplifiers available within one or two years.
Fujitsu says it discovered that problems such as device failure and unstable output at high drive voltages were caused by non-uniformity and defects in the GaN epitaxial layer. By optimizing epitaxial growth conditions, Fujitsu’s device could operate at a very high voltage.
The company says that the HEMT amplifier also satisfies the W-CDMA specification for adjacent channel leakage – the degree to which adjacent signals are affected by amplifier distortion.
Until now, the power output of GaN HEMTs had been limited to 100W at 50V, says Fujitsu. Applying higher voltages not only made device failure more likely, but also affected power stability at high frequencies, lowering power output and efficiency.
Fujitsu is presenting details of the technology at the International Electron Devices Meeting in Washington, DC today.
