Transistors for UHF TV power amplifiers broadens RF device portfolio

October 11, 2013 // By Paul Buckley
Infineon Technologies has introduced 50 V LDMOS transistors designed for use in UHF TV broadcast transmitters, including one device that claims to provide the highest peak power output available for this application.

The higher power output across the entire 470 – 806 MHz TV broadcast band gives amplifier designers the option to use fewer transistors to achieve target output power, which translates to cost savings due to lower component count and higher reliability as a result of simpler design.

The high power PTVA047002EV has a rated power output of 135 W average, which is 8% greater than other available devices, with a DVB-T (8k OFDM) signal, and 17.5 dB gain. For a broadcast amplifier design of 12 kW, the increased power can eliminate up to 20 RF power transistors representing a reduction in total system cost while increasing reliability due to simpler, lower component count design. The lower power PTVA042502EC and PTVA042502FC transistors provide 55W average output power and 18.5 dB gain with a DVB-T (8k OFDM) signal, which makes them well-suited for applications such as gap fillers.

Excellent efficiency, typically 26% at 500 MHz, reduces heat output. The efficiency is complemented by low thermal resistance (Rth 0.20C/W) of the package, a characteristic of Infineon’s 50 V LDMOS technology that allows for better thermal management and smaller heat sink designs. This further contributes to lower cost and higher reliability.

Other important features shared by all Infineon 50 V LDMOS transistors include high ruggedness (able to withstand 10:1 VSWR load mismatch with 3 dB input overdrive), wide gate source voltage range (-6 V to 12 V), and integrated ESD protection.

Complete reference design/evaluation board kits, including Gerber files and related documentation, are available. The PTVA047002EV is available in an open-cavity 275-style package with eared flange. The PTVA042502EC and PTVA042502FC are available in an open-cavity 248-style package with eared and earless flange respectively.