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At this week’s IEEE MTT-S International Microwave Symposium (IMS 2008) in Atlanta, TriQuint Semiconductor Inc of Hillsboro, OR, USA has launched two new 28V HV-HBT (high-voltage heterojunction bipolar transistor) devices created at TriQuint’s design center in San Jose, CA, formerly WJ Communications (acquired in May for $72m). Samples of the high-dynamic-range two-stage HBT amplifiers will be available in July.

The highly efficient, highly linear 4W AP631 and 7W AP632 devices expand TriQuint’s HV-HBT portfolio. WJ’s expertise in InGaP HBT technology, paired with TriQuint’s high-power HBT devices, provide a complete RF transistor solution for 3G/4G high-power amplifier (HPA) mobile infrastructure designs, says TriQuint. “WJ’s device line-up complements our base-station portfolio very well,” adds product marketing director Dan Green. Greater amplifier efficiency can enable lower initial base-station costs, lower power consumption and lower operating costs. The role of highly efficient, highly linear RF transistors in base-station amplifier design is critical to enabling network operators’ plans for meeting 3G/4G service demands, Green notes. “GSM system amplifiers (2G) don’t require linear operation, and their efficiencies were much higher because of this fact. But next-generation 3G/4G systems demand linearity and efficiency, so technology that was well suited to older network systems suffered a setback when deployed in WCDMA or other next-generation platforms,” he adds. “Consequently, early 3G network operators saw dramatic increases in operational expenditure (OpEx) due to the loss of efficiency, so they sought solutions.”

The new, relatively low-power HBT devices are suited to use as pre-drivers and drivers in the base-station’s RF section. They follow the released last October of TriQuint’s first generation of high-power HV-HBT devices, which serve as the driver and output stages and provide exceptionally high efficiency and linearity. Collectively, the devices form a complete RF solution.

“Efficiency at the driver and output stages is especially critical, since these components have the greatest impact on minimizing electrical consumption, and play a significant role in reducing the waste heat generated in the RF section of an amplifier,” says Green. “Because our high-power HV-HBT devices are so efficient, they generate about half the waste heat of competing technology in WCDMA systems [reducing electricity usage by cooling systems],” he claims.

“Efficiency at the driver and output stages is especially critical, since these components have the greatest impact on minimizing electrical consumption, and play a significant role in reducing the waste heat generated in the RF section of an amplifier,” says Green. “Because our high-power HV-HBT devices are so efficient, they generate about half the waste heat of competing technology in WCDMA systems [reducing electricity usage by cooling systems],” he claims. The new HBTs come at a time of continued growth for highly linear RF transistors in the base-station networks market. According to EJL Wireless Research in the 4th edition of its ‘Global BTS Transceiver Market Analysis and Forecast, 2007-2012’ from this April, the growth in demand for 3G and 4G base-stations will result in a 2008-2011 compound annual growth rate (CAGR) for high-linearity transceivers of 35%. These systems require highly linear amplifiers, particularly with the ‘unprecedented’ levels of efficiency provided by TriQuint’s HV-HBT devices, the firm claims.

The new HV-HBT devices integrate two stages into a single package, allowing a reduction in the number of discrete amplifier components in a system. When used in a typical base-station HPA design, a 25% cost reduction and a PCB area savings of 12cm2 can be achieved compared to designs using two separate discrete amplifier stages.

The new amplifiers’ high linearity minimizes additional signal distortion for repeater applications when used in final amplifier stages, and reduces backoff power requirements to minimize distortion from high PAR (peak-to-average ratio) signals in 3G/4G mobile base-stations. This translates into reduced overall system costs and improved efficiency, which can lower HPA power consumption and improve OpEx for multi-carrier 3G mobile infrastructures.

See related items:

TriQuint launches its first high-frequency GaN products

TriQuint’s profits hit by military/network R&D costs

TriQuint to acquire WJ for $72m

Search: TriQuint InGaP HBT Base-station

Visit: www.triquint.com