At the Hawaiian Convention Center in Honolulu this week, RF power transistor vendors from the West and the East convened at the IEEE’s MTT-S International Microwave Symposium to showcase their latest developments in LDMOS, gallium arsenide (GaAs) and gallium nitride (GaN) transistors. While Freescale Semiconductor unveiled seven new LDMOS RF power transistors to enable WCDMA and CDMA2000 base station transmitters to exploit the full potential of Doherty amplifier architecture, NXP Semiconductor displayed its Gen6 LDMOS portfolio for mobile WiMAX and other wireless applications. TriQuint Semiconductor announced two 0.15µm GaAs pHEMT-based satellite communications (Satcom) high-power amplifiers (HPAs) that boasted improved performance with overall size reduction. Nitronex, Cree, Eudyna and Toshiba demonstrated new capabilities in GaN power transistors.

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Speaking of LDMOS, Freescale’s new devices are tailored for signals with high peak-to-average (PAR) ratios. Covering cellular, PCS and WCDMA frequencies, two of the devices (MRFE6S9205H/HS and MRFE6S9135H/HS) operate in 865 MHz – 960 MHz band, two other (MRF6S19200H/HS and MRF6S19140HR3/HSR3) in the 1930 MHz – 1990 MHz band, and three (MRF7S21170HR3/HSR3, MRF6S21190HR6 and MRF6S21140HR3/HSR3) in the 2110 MHz – 2170 MHz. In addition, the supplier also released a 1 kW pulsed RF output LDMOS at 130 MHz with highest drain efficiency and power. Operating at 50 V, the MRF6VP11KH provides designers of high-power systems such as magnetic resonance imaging (MRI) systems, CO₂ lasers, plasma generators and other systems with significant benefits when compared to bipolar and MOSFET devices, stated Freescale..

On the GaN front, Nitronex disclosed a 4 W GaN-on-Si pre-driver power transistor designated NPTB00004. At 900 MHz, the NPTB00004 power transistor has input/output impedances near 50 ohms, reducing the need for external matching circuits. Under WCDMA modulation at 2.1 GHz, the power transistor typically delivers 14.5 dB of power gain, 25% efficiency at an ACPR of -45dBc.

“The NPTB00004 provides improved power and efficiency for a given linearity compared to existing solutions in the pre-driver market,” said Chris Rauh, Nitronex vice president of sales and marketing. “We believe the combination of our SIGANTIC process and the qualified low-cost plastic overmold packaging assembly at Amkor Technology, Inc. is a winning combination for designers.” It is sampling now with full production qualification expected in August.

Likewise, Cree announced sample availability of three new GaN HEMT devices especially designed for WiMAX applications. These include CGH27120, CGH27060 and CGH27030, offering linear power up to 16 W under OFDM modulation in small-footprint packages.

While Japan’s Eudyna Devices displayed an 800 W AlGaN/GaN HEMT, operating at 65 V drain bias voltage for S-band high power application, Toshiba America Electronic Components Inc. (TEAC) revealed its first commercially available X band GaN HEMT for radar systems and medical applications. Designed for 8.5 GHz – 9.6 GHz with output power of 50 W, the TGI8596-50 is an internally matched GaN HEMT that features 3 dB compression point of 47.5 dBm (typical), linear gain of 9.0 dB (typical), and drain current of 4.5 A (typical). “As a follow-on to this initial device, Toshiba is also developing C and Ku band GaN HEMTs for satellite communications applications,” said Homayoun Ghani, business development manager for TAEC’s microwave, logic and small signal devices.