RF transistor is ready for TV switchover

The latest addition to Freescale's family of RF power LDMOS transistors is designed for TV transmitters employing both analogue and digital modulation formats.

Freescale Semiconductor has introduced a 50V laterally diffused MOS (LDMOS) RF power transistor designed to deliver 50% 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 450W peak power at P1dB with 50% 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 analogue and digital modulation formats.

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 MRF6VP3450H, can help reduce this cost by converting a greater%age 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 minimising 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", says 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 minimise 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 860MHz TV broadcast operation.

Using a DVB-T 64 QAM OFDM signal at 90W average output power, the typical 860MHz 50V performance is 28% drain efficiency and 23dB gain, with an adjacent channel power ratio (ACPR) at 4MHz offset of -62dBc in a 4kHz bandwidth.

In addition to offering exceptional figures of merit, the MRF6VP3450H device can help ease the transition from analogue to digital TV broadcast.

The global broadcast industry is moving rapidly to digital modulation from the analogue modulation schemes that have been employed for more than 70 years.

After February 2009, digital broadcasting will replace all analogue 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 device is based on Freescale's sixth-generation, high-voltage (VHV6) 50V LDMOS process technology.

This advanced technology has resulted in major breakthroughs, including the first 1kW LDMOS FET and the first 300W UHF RF power transistor for broadcast applications in over-moulded plastic packaging.

Freescale's broadcast portfolio now includes 32 and 50V devices covering 10 to 860MHz at power levels from 10W to more than 1kW - the widest range of power levels available in the industry.

All devices in the portfolio are RoHS compliant.

The MRF6VP3450H is extremely rugged and is designed to handle very high impedance mismatches without damage.

For example, operating at 50V and 90W average DVB-T OFDM, it can survive all phase angles of a 10:1 VSWR.

Similarly, it will survive the same mismatch operating at 450W peak pulsed power (10us pulse, 2.5% duty cycle).

The device also incorporates protection against electrostatic discharge (ESD), which makes it less susceptible to damage during handling and manufacturing.

The MRF6VP3450H is sampling now, and full production is expected in Q3 2008.

A reference test fixture is available from Freescale today, and a large-signal model is expected in Q4 2008.

Back to top