Freescale has introduced an RF power LDMOS transistor. The MRFE6VP8600H delivers 39 percent greater output power than its predecessor and is designed to deliver maximum performance for many key digital transmission standards including ATSC, DVB-T and ISDB-T. The MRFE6VP8600H provides significant benefits for television transmitter manufacturers and broadcasters.

For example, the transistor delivers 125W of linear power (more than 600W peak envelope power) over the entire broadcast band, with exceptional efficiency (typically 30 percent at 860 MHz and up to 45 percent when employed in a Doherty configuration). The UHF frequency band ranges from 470 MHz to 860 MHz and is used by broadcasters to transmit television signals over the air.

The vast majority of television stations currently broadcasting in digital are using the UHF band. When driven to its full rated RF output power, this device will not degrade in performance when driving an impedance mismatch (VSWR) greater than 65:1, at all phase angles, or when driven by twice its rated input power.

The transistor’s ruggedness makes it far more reliable under adverse conditions such as antenna icing, transmission line failure or operator error, even with drive peaks created by predistortion systems. In addition, the MRFE6VP8600H easily tolerates the out-of-band reflective load conditions caused by highly selective channel filters and the high peak-to-average ratio (PAR) characteristic of digital transmission schemes employing higher-order modulation techniques such as DVB-T (8k OFDM). The enhanced ruggedness characteristics of the MRFE6VP8600H also make it possible to employ simplified transmitter protection circuits.

Key specifications

• 125W average RF output power (DVB-T [8k OFDM] signal) at 860 MHz, gain of 19.3 dB and efficiency of 30 percent
• 600W peak RF power
• Can be designed into Class AB, Doherty or drain modulation amplifier architectures, eliminating the need for a specific device optimized for each architecture
• Integrated electrostatic discharge (ESD) protection to provide resistance to stray voltages encountered during assembly
• Extended negative gate-source voltage range of -6V to +10V to improve performance when operated as the peaking stage of a Doherty amplifier

Housed in Freescale’s NI-1230 bolt-down ceramic air cavity package (MRFE6VP8600H) or NI-1230S solder-attach ceramic air cavity package (MRFE6VP8600HS) The MRFE6VP8600H/HS is now in production. A broadband reference design and other support tools are available to designers