Last week, NXP Semiconductors announced the availability of a new LDMOS UHF RF power transistor, the BLF888A, for use in broadcast transmitters and industrial applications. The unit is rated at 600 Watts, and in DVB-T use, can deliver 120 Watts average output power with efficiencies greater than 31 percent. I did not find any ATSC specifications; however, as ATSC has a lower peak-to-average ratio I would expect that the transistor could deliver more power when transmitting ATSC signals. It has a gain of 21 dB and can handle VSWRs greater than 40:1.
"The exceptional performance of the BLF888A is enabled by NXP's 50V high voltage LDMOS process technology in combination with advanced thermal concepts, resulting in unprecedented power density and thermal resistance as low as 0.15K/W," according to the NXP news release.
Mark Murphy, NXP director of marketing for RF power products, said, "We have achieved something very special with the BLF888A, by being able to combine excellent ruggedness with broadband power and efficiency. In the past, designers would have had to trade these parameters off against each other, yielding a sub-optimal solution. Now with the BLF888A, broadcast transmitter architects around the world have the option to optimize the RF system level performance without having to worry about the power transistor."
More information and links can be found in the BLF888A product page and the in the data sheet.
Harris Introduces New UHF Transmitters Built With New Freescale LDMOS Devices
Harris Corp. showed the result of this collaboration at IBC with its Maxiva line of TV transmitters.