50V LDMOS transistors for UHF TV power amplifiers

11th October 2013

Nat Bowers

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Infineon Technologies introduce 50V LDMOS transistors designed for use in UHF TV broadcast transmitters, including one device providing 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 135W average, which is eight percent greater than other available devices, with a DVB-T (8k OFDM) signal, and 17.5dB gain. For a broadcast amplifier design of 12KW, the increased power can eliminate up to 20 RF power transistors representing a significant 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 18.5dB gain with a DVB-T (8k OFDM) signal, which makes them well-suited for applications such as gap fillers.

Excellent efficiency, typically 26 percent at 500MHz, reduces heat output. This is complemented by low thermal resistance (Rth 0.20 degree C/Watt) of the package, a characteristic of Infineon’s 50V 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 50V LDMOS transistors include high ruggedness (able to withstand 10:1 VSWR load mismatch with 3dB input overdrive), wide gate source voltage range (-6V to 12V), and integrated ESD protection.

Engineering samples of the new UHF TV broadcast power transistors are available now, with production ramp beginning in this calendar quarter for the PTVA042502EC and PTVA042502FC. Production ramp for the PTVA047002EV is planned for the first quarter of 2014. Complete reference design/evaluation board kits, including Gerber files and related documentation, also 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.