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21 March 2007

Cree samples GaN HEMTs that boost WiMAX PA efficiency by up to 50%

Cree Inc of Durham, NC, USA says that it is shipping sample quantities of three new gallium nitride high-electron-mobility transistors (HEMT). Optimized for high efficiency, high gain and wide bandwidth, the devices provide exceptional linear power and efficiency for WiMAX and broadband wireless access applications operating at 2.3-3.9Ghz, the firm claims.

The CGH27015S (contained in a small 3mm x 3mm plastic over-mold QFN package) operates over the 2.3-2.9GHz frequency range, with typically 2.5W of average output power and 28% drain efficiency (an improvement of up to 40% over traditional technologies such as silicon LDMOS or GaAs under 802.16-2004 WiMAX signals and requirements). Also, small-signal gain is 15dB and error vector magnitude (EVM) is 2.0% under orthogonal frequency-division multiplexing (OFDM) modulation when operated at 28V.

The CGH35015S (also in an over-mold QFN package) operates over the 3.3-3.9GHz frequency range, with typically more than 2.5W of average output power and 28% drain efficiency (up to a 50% improvement). Typical small-signal gain is 13dB.

The CGH35030F operates over the 3.3-3.9GHz frequency range with 4W of average output power and 23% efficiency. Small-signal gain is more than 11dB and error vector magnitude (EVM) is 2% under OFDM modulation.

When used in an efficiency-enhancement circuit, a pair of these transistors produced more than 10W of average power with over 42% efficiency in the 3.5GHz WiMAX band.

The CGH27015S and CGH35015S plastic over-mold GaN transistors allow the use of low-cost, high-speed assembly methods, while preserving outstanding RF performance with a RoHS-compliant device, says Jim Milligan, business area manager for RF products. "The CGH35030F provides further flexibility for RF designers needing additional power at high efficiency to enable new system architectures such as distributed wireless base stations employing remote radio heads,” he adds.

Visit: http://www.cree.com/wireless