Durham, NC — Cree has released two 120W, highly efficient GaN HEMT microwave transistors in sample quantities for telecommunication applications such as W-CDMA, LTE and WiMAX. Due to the unique combination of high RF power density, low capacitance and high thermal conductivity silicon carbide (SiC) substrates, these transistors provide superior performance compared to other technologies such as GaAs MESFET or Si LDMOSFET. Two demonstration amplifiers — one for each device — are available for transistor evaluation.
The transistors consist of single, input-pre-matched GaN HEMT devices providing more than 120 W of saturated power in small, industry-standard ceramic-metal packages. These transistors provide convenient values of input and output impedances to allow device matching over greater than 30 percent instantaneous bandwidths.
The CGH21120F is designed to be used primarily in the 1800 to 2300 MHz frequency range, while the CGH25120F is optimized for the 2300 - 2700 MHz range. This allows the two transistors to be used for DCS (GSM), PCS (GSM and CDMA), W-CDMA, and LTE.
As an example, the CGH21120F provides more than 110 W of peak CW power at 70 percent efficiency with a gain of 16 dB when operated at 28 V. Under W-CDMA 3GPP stimulus, the transistor provides 25 W average power with 40 percent efficiency in Class A/B operation. According to the company, this is the highest known W-CDMA efficiency from any commercially available transistor at this power level.
"High efficiency is becoming a driving factor, along with increased emphasis on higher average powers, for multi-channel/carrier applications," said Jim Milligan, Cree director of RF and microwave products.
According to the company, these transistors also allow a high degree of digital pre-distortion correction so that ACLRs (Adjacent Channel Level Ratios) of -60 dBc can be routinely achieved. In a recent demonstration, two CGH21120F transistors, in a Doherty amplifier configuration, generated 80 W of average power under W-CDMA with a record efficiency of 52 percent.
The CGH21120F and CGH25120F complement the range of the company's RoHS-compliant HEMT microwave transistors for WiMAX applications available for 802.11x OFDM average power levels of 2 W, 4 W and 8 W.
For further information visit www.cree.com.