Tuesday, June 16, 2009

LDMOS Transistors Aid Design Of Wireless Stations

Infineon Technologies AG has introduced a range of high-power LDMOS transistors for the design of broadband wireless-network base stations. The transistors, introduced at the IEEE MTT-S International Microwave Symposium, feature power levels up to 300W and video-bandwidth exceeding 90MHz. They support the high peak-to-average power ratios and high data-rate specifications required for the evolution from 3 to 4G wireless networks.

The new transistor range achieves higher gain and higher power-density than alternative devices operating in the 1.4 - 2.6GHz cellular bands. This allows the use of packages with a 30 per cent smaller footprint, to enable smaller and lower cost amplifier designs. High peak-power is valuable for Doherty-based amplifier designs, as well as for reducing parts count in other architectures. Illustrative performance of the new transistors, in a two-carrier WCDMA signal at 2170 MHz, 30V, 8dB PAR and 3.84MHz channel bandwidth, is: 50W average power, 18dB gain and 28 per cent efficiency (using a transistor with P-1dB output power of 230W).

A 300W (P-1dB) device in the same application measures 65W average power, 18dB gain and 28 per cent efficiency. All the new PTFB transistors are offered in open-cavity ceramic packages for bolt-down or earless mounting. They are Pb-free and ROHS compliant. Samples of the first six products are now available.

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