Freescale optimizes 50V LDMOS RF transistor line-up for TV broadcast transmitters

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 21 dB 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 (ACPR) at a 4 MHz offset is -68 dBc over a 4 kHz integration bandwidth. As an analog or digital TV final for low power repeaters, the device has typical UHF broadband performance of greater than 40 percent efficiency, 21 dB gain and an IM3 of less than -30 dBc.