Freescale has developed an RF power LDMOS transistor that combines high output power and efficiency with ruggedness, for UHF broadcast television applications.
The MRFE6VP8600H delivers 39% greater output power than its predecessor – 125W of linear power (more than 600W peak envelope power) over the entire broadcast band, with impressive efficiency (typically 30% at 860 MHz and up to 45% when employed in a Doherty configuration, according to Freescale).
The company says the part’s higher RF output and greater efficiency can reduce the total number of transistors and combiner stages needed for a given output power. A transmitter based on the MRFE6VP8600H can use up to 15% less power than previous generations.
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 very 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 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).