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Freescale Semiconductor has introduced a 50 V laterally diffused MOS (LDMOS) RF power transistor designed to deliver 50 percent higher output power than competing UHF TV broadcast solutions.
Demonstrating industry-leading RF figures of merit, the MRF6VP3450H device offers the highest output power in its class for UHF applications while enabling system-level power reductions that can potentially save broadcasters thousands of dollars in operating costs. The MRF6VP3450H delivers more than 450 W peak power at P1dB with 50 percent efficiency throughout the UHF broadcast frequency band.
The latest addition to Freescale’s growing family of RF power LDMOS transistors for broadcast applications, the MRF6VP3450H is designed for TV transmitters employing both analog and digital modulation formats. Transmitters represent a significant operating cost for TV broadcasters. A leading contributor to this operating cost is the power consumed by RF power amplifiers.
Highly efficient RF power transistors, such as the MRF6VP3450H, can help reduce this cost by converting a greater percentage of the required AC input power into RF output power. Ultimately, this efficiency reduces the energy usage required by the transmitter. In addition, individual transistors with higher RF power capability enhance system-level efficiency by minimizing device count and combining losses.
“As energy costs continue to soar, the ability to use highly efficient, cost-effective TV transmitters is critical to broadcasters,” said Gavin P. Woods, vice president and general manager of Freescale’s RF Division. “Transmitters designed with our new MRF6VP3450H device not only deliver dramatic annual energy savings, but also can significantly reduce transmitter cost by helping to minimize the number of required RF power transmitters.”
The MRF6VP3450H device is designed to offer the best combination of power, efficiency and gain of any RF power transistor designed for 470 to 860 MHz TV broadcast operation. Using a DVB-T 64 QAM OFDM signal at 90 W average output power, the typical 860 MHz 50 V performance is 28 percent drain efficiency and 23 dB gain, with an adjacent channel power ratio (ACPR) at 4 MHz offset of -62 dBc in a 4 kHz bandwidth.
In addition to offering exceptional figures of merit, the MRF6VP3450H device can help ease the transition from analog to digital TV broadcast. The global broadcast industry is moving rapidly to digital modulation from the analog modulation schemes that have been employed for more than 70 years. After February 2009, digital broadcasting will replace all analog modulation schemes in the United States, and broadcasters worldwide will soon be “fully digital.” This conversion to digital broadcasting places significant demands on a transmitter’s power amplifier and RF power transistors because the signals have very high peak-to-average ratios. As a result, RF power transistors used for the conversion must exhibit extremely high linearity under a wide range of operating conditions, as well as high efficiency and ruggedness to ensure long operating life.
The MRF6VP3450H is sampling now, and full production is expected in the third quarter of 2008. A reference test fixture is available from Freescale today, and a large-signal model is expected in the fourth quarter of 2008.
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