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Further optimizing its sixth-generation, high-voltage LDMOS process to 42 V, NXP Semiconductors has raised the performance for its RF LDMOS power transistors. As a result, the newly launched BLF878 boasts true 300 W capability in the UHF band from 470 MHz to 800 MHz. In fact, the power transistor is capable of delivering 300 W over the full UHF band with outstanding linearity and ruggedness, stated Guido Bekkers, worldwide marketing manager for NXP's RF Power Broadcast and Microwave. It is being targeted at the TV transmitter/broadcast market.

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To transmit the huge amounts of data necessary to beam DVB-T and DVB-H (digital video broadcasting) programming to homes, high-performance TV broadcasters are seeking the maximum power available. The BLF878 UHF power LDMOS transistor enables this, maximizing power output from available input and increasing efficiency to 45% continuous wave (CW) and 32% for digital broadcasting, resulting in huge cost savings for broadcasters, noted Bekkers.

Besides high linearity, the UHF power LDMOS transistor also offers a highly robust solution, capable of withstanding the rigors of high-performance broadcast operations with a voltage standing-wave ratio (VSWR) of 10:1.

Other key features include a power gain of 19 dB, drain efficiency of 45% and third-order intermodulation distortion of -32 dBc, obtained for a two-tone performance at 860 MHz with a drain-source voltage (V_DS) of 40 V and a quiescent current of 1.4 A. Likewise, for DVB performance at 858 MHz with a V_DS of 40 V and a quiescent current of 1.4 A, the UHF LDMOS transistor's average output power is 75 W, power gain is 19 dB and drain efficiency is 32%. The UHF LDMOS is housed in a four-lead ceramic package that incorporates special laminate to handle high-power dissipation. Hence, typical thermal resistance from junction to case is 0.23 K/W, and from junction to heat sink is 0.37 K/W. Plus, to achieve high output power, the device is internally matched.

In addition, the supplier has developed a 100 W driver for the high-power transistor. Labeled BLF871, its peak envelope load power is rated at 100 W when measured for a two-tone performance at 880 MHz with a V_DS of 40 V and a quiescent drain current of 500 mA.

Meanwhile, the manufacturer is readying a new family of 50 V high-voltage LDMOS transistors aimed at the industrial, scientific and medical (ISM) band.

According to NXP, the BLF878 UHF power LDMOS transistor will be sampling to selected customers in the third quarter, with production slated for the fourth quarter.
NXP Semiconductors
(800) 447-1500
www.nxp.com