Power transistor streamlines UHF transmitter design

Freescale Semiconductor has released the MRF6V3090N RF power transistor that is designed to streamline UHF transmitter equipment designs. The 50V LDMOS transistor when combined with MRF6VP3450H enables system-level power reductions that can potentially save broadcasters thousands of dollars in operating costs.

Transmitters represent a significant operating cost for TV broadcasters, and a leading contributor to this operating cost is the power consumed by RF power amplifiers. Highly efficient RF power transistors, such as the MRF6V3090N and MRF6VP3450H, can help reduce this cost by converting a greater percentage of the required DC input power into RF output power. In addition, individual transistors with higher RF power capability enhance system-level efficiency by minimizing device count and combining losses.

The latest addition to Freescale's growing family of RF power LDMOS transistors for broadcast applications, the MRF6V3090N is designed for TV transmitters employing both analog and digital modulation formats. The MRF6V3090N delivers 90W peak power at P1dB with greater than 40 percent efficiency through the UHF broadcast frequency band.

As a linear driver, the MRF6V3090N achieves 21dB power gain and drain efficiency of 12 percent with an average output power of 4.5W, based on a DVB-T OFDM signal. The adjacent-channel power ratio at a 4MHz offset is -68dBc over a 4kHz integration bandwidth. As an analog TV or DTV final for low power repeaters, the device has typical UHF broadband performance of greater than 40 percent efficiency, 21dB gain and an IM3 of less than -30dBc.

Housed in Freescale's over-molded plastic packaging technology, the MRF6V3090N can be used in a single-ended or push-pull configuration. This enables design engineers to use the device in multiple applications and bands requiring high gain and efficiency.

The transistor is sampling now, and full production is expected in Q4 09. A reference test fixture is available to aid in the evaluation and design process.

For application notes on transistors click here.