GaN Transistors Reach For High Power And Linearity
Cellular base-station developers face an ongoing quest for higher output power levels and improved linearity. To meet these high linearity and power requirements, many power transistor suppliers, including Eudyna Devices (San Jose, CA), are turning to gallium-nitride (GaN) semiconductor materials. Eudyna's commitment to GaN research and development has resulted in a full line of devices ranging in output-power levels from 30 to 180 W and usable at frequencies past 3.5 GHz for both cellular and WiMAX wireless applications.
Eudyna, of course, is the consolidation of the compound semiconductor operation of Fujitsu Quantum Devices Ltd. and the similar arm of Sumitomo Electric Devices Ltd. The two business units were merged into the joint venture company Eudyna Device, Inc. in 2004 with one goal targeting the development and marketing of next-generation high-power, high frequency transistors. The new devices are GaN high-electron mobility transistors (HEMTs), fabricated on a semiconductor material that has been of interest to commercial and military researchers because of its excellent output power density at high current and high voltage conditions. Most base-station developers would like to achieve high output power with a minimum number of devices (and power-combining stages), implying the use of high-power-density semiconductor materials.
The lowest-power members of the Eudyna GaN transistor lineup are the 30-W models ES/EGN26A030MK and ES/EGN35A030MK. Both are suitable for use in broadband power amplifiers operating at 50 V. Model ES/EGN26A030MK features 13 dB gain at 3.5 GHz with +46 dBm typical output power at 3-dB gain compression. It has 55 percent typical efficiency at 3-dB compression. Model ES/EGN35A030MK achieves 15-dB linear gain at 2.6 GHz with +46.5 dBm typical output power at 3-dB gain compression. It exhibits 60 percent typical efficiency at 3-dB gain compression. Both 30-W transistors show a typical breakdown voltage of 350 V with gate-source current of 5.6 mA.
Next in the GaN HEMT lineup are the 90-W models, also designed for 50-V operation. Model ES/EGN26A090IV provides 14 dB typical linear gain at 2.6 GHz. It delivers +50 dBm typical output power at 3-dB gain compression, and boasts 55 percent efficiency at 3-dB compression. Designed for somewhat higher-frequency use, model ES/EGN35A090IV features 12 dB typical linear gain at 3.5 GHz. It generates +50 dBm output power at 3-dB gain compression,, and operates with 50 percent typical efficiency at 3-dB gain compression. The devices draw 18 mA drain-source current at +50 VDC.
The highest-power devices in the current GaN HEMT lineup are the 50-V, 180-W models ES/EGN35A180IV and ES/EGN26A180IV (see figure). The lower-frequency model ES/EGN26A180IV offers 14-dB linear gain at 2.6 GHz. It generates +53 dBm output power at 3-dB gain compression, and operates with 55 percent typically efficiency at 3-dB gain compression. Model ES/EGN35A180IV achieves linear gain of 12 dB at 3.5 GHz. It achieves +53 dBm output power at 3-dB gain compression and boasts efficiency of 50 percent at 3-dB gain compression. The devices draw 72 mA current at +50 VDC.
All of the power transistors are supplied in flange-mounted ceramic packages.
Eudyna Devices USA, Inc., 2355 Zanker Rd., San Jose, CA 95131-1138; (408) 232-9500, FAX: (408) 428-9111, Internet: www.eudyna.com