3G Base Station Amplifiers That Can Reduce Waste Heat Nearly 50%

TriQuint Semiconductor has announced the availability of a new generation of high-voltage gallium arsenide (GaAs) power amplifier transistors designed to substantially increase the efficiency of 3G cellular base stations, which can lead to greater energy savings. The company says that this efficiency improvement will support the development of base stations that incorporate smaller, less expensive, and more energy efficient cooling systems.

TriQuint tested the first of its new HV-HBT amplifiers in a design commonly used by base station amplifier manufacturers that pairs devices in a 'Doherty' configuration. Used in this manner, the devices delivered an efficiency level of 57%, surpassing the efficiencies available using either conventional laterally-diffused metal oxide semiconductor (LDMOS) transistors or more expensive gallium nitride (GaN) devices.

The importance of this next-generation in amplifier design will be seen as high bandwidth wireless markets continue to expand.

According to a 2007 study by Strategy Analytics, 3G and 4G base transceiver station (BTS) power amplifier shipments are expected to increase at a compound annual growth rate (CAGR) of approximately 19% through 2010. These estimates do not include an expansion of the global WiMAX market that could also employ a TriQuint HV-HBT transistor.

"GSM system amplifiers don't require linear operation, and their efficiencies have traditionally been much higher than amplifiers for 3G systems. Network operators that have deployed 3G systems in the past few years have seen a dramatic increase in OPEX costs related to electricity," remarked Mike Sanna, TriQuint Semiconductor Vice President of Network Products.

"Those operators have gone back to the base station OEMs and amplifier companies with aggressive efficiency goals for existing 3G and next-generation 4G systems to get those costs back under control. TriQuint's HV-HBT transistors will provide a significant 'step-function' improvement in amplifier efficiencies. For example, one of our lead customers reports up to a 10 point increase in amplifier efficiency when using our TGH2932-FL devices, which is significant."

How much TriQuint's new amplifier design will save network operators depends on several variables including the cost of electrical power in a given area, what cooling systems are employed by the base station manufacturer, and many other factors. But a good way to illustrate the savings is to consider that for a 50W average power WCDMA amplifier design, the new TriQuint transistors create only about 38 Watts of waste heat, which is less than the heat produced by an average household light bulb. LDMOS transistor-based amplifiers used in 3G systems today generate as much as 70 Watts of waste heat. TriQuint's amplifier reduces waste heat by nearly 50% in comparison.

"A transistor this efficient provides several paths to savings. The immediate opportunity is to realize overall savings in existing style systems, which will generate less waste heat, reduce air-conditioning expense, cut heatsink size, and require fewer cooling fans. The longer term opportunity is the potential to eliminate the ground based amplifier in exchange for a tower top amplifier. That would result in a much more dramatic reduction in both energy consumption and equipment cost. In general, a more efficient amplifier enables radio designs that are far less focused on mitigating the damaging effects of heat, which is a key design consideration today," Sanna concluded.

Posted to the site on 3rd October 2007