GaAs firms ready PA revolution

The depiction of the current recession has in some places neared that of a financiers-jumping-out-of-windows crisis. Following mainstream news, it seems inconceivable that 47,000 delegates attended the GSM Association s Mobile World Congress (MWC) in Barcelona in February. Yet they did, even if the drop in attendance from 55,000 in 2008 and ensuing fall in exhibition traffic caused dissatisfaction. Although GaAs manufacturers booths were among the most deserted, each company had a clear vision of where they expect the industry to head this year.

A more realistic picture of the world s financial situation was painted by economist Jeffrey Sachs, advisor to UN Secretary-General Ban Ki-Moon. He summarized the scale of the challenge faced by the wireless industry in the face of the recent $35 trillion decline in paper wealth. Although that figure is roughly 70% of one year s global income and has shocked consumers into a major spending decline, he does not believe that the world will see a 1930s-style "great depression". He said that emerging markets would lead the way out of the recession, and that wireless communication will have a crucial part to play both there and in the wider economy.

"The technologies that are embodied by this sector are a source of massive productivity gains and massive inclusion of different parts of the world that lead directly to their economic empowerment," Sachs said. "This is true from the poorest villages in the world to the largest market."

The biggest opportunity in the developing world energizing the MWC was from the licenses granted by China to operators of third-generation (3G) mobile networks. Among GaAs chip manufacturers, RF Micro Devices (RFMD) has released a revitalized range of power amplifiers (PAs) to capitalize on this, targeted at the CDMA transmission standards covered by the Chinese licenses. Skyworks Solutions also launched a range of five wideband CDMA PAs that it claims are the smallest on the market. Meanwhile, TriQuint Semiconductor is relishing the increased demand that network rollouts may herald for its base station component business.

There was a feeling of welcome surprise from some in the GaAs community that China chose to grant all three licenses at the same time. Granting only the license for the China-specific TD-SCDMA 3G protocol first would have given home-grown manufacturers an advantage. By releasing all three, China has given the wider industry an early taste of the power of fiscal stimulus.

Hopes for a quick follow-up with Indian 3G network licenses were dashed, however, as news emerged of conflict with the country s military needs. The licenses, initially slated for January, now look set to be granted in the second half of 2009.

With 3G handsets often containing more than three PAs, the expansion of the technology across the globe looks like good news in terms of GaAs manufacturing volumes. Currently, several different PAs ensure that mobile devices are able to communicate with networks using protocols from 2G GSM up to wideband CDMA and HSUPA – the highest-speed 3G transmission standard. However, PA making firms are now vying to integrate these functions into a single PA module and thus reduce GaAs costs for handset makers. In Barcelona both TriQuint and RFMD unveiled their integration strategies. Converge and control TriQuint s Unified Mobile Front-End, or Triumf, will bring together what is typically one PA module for GSM, GPRS and EDGE standards and three wideband CDMA and HSUPA PA-duplexer modules. "This has two advantages," Paul Cooper, strategic marketing manager for handset products at TriQuint, told Compound Semiconductor.

"It has an advantage for the mobile device manufacturer of a single source for all of the PAs, one preferred vendor, lower assembly costs and a smaller size. It s an advantage for us because [where currently] we may be mixed and matched with different vendors, we re getting all of the PA spots in one." Other than this, Cooper would not be drawn on the technical details of the development-stage architecture, which is unlikely to earn revenue until 2010.

RFMD s RF6460 converged architecture is also still in development, in collaboration with a platform provider that supplies the basic systems underlying brand-name handsets. That effort has already shown in the lab that it s possible to combine the necessary signals. RFMD says that it also has a head start in developing converged architectures thanks to previously released RF3267 and RF6266 combined wideband CDMA/HSDPA PAs that it is shipping in volume to Samsung.

"If you were to imagine this solution minus the GSM/EDGE, the multiband capability through wideband CDMA/HSPA, this is a solution that we ve been shipping to tier-one customers for about two years," said Ben Thomas, business development manager for RFMD s components business unit. "The challenge is taking that solution, adding a mode switch, which leverages our PHEMT technology, and adding the capability to do GSM/EDGE."

RFMD will begin sampling the RF6460 in the second half of 2009, with full release dates expected to be announced in 2010.

Despite the competition between their products, there are common strategic elements underlying RFMD and TriQuint s approaches to converged front ends. For example, as well as offering lower costs and simpler design these products must increase the length of call time in between phone recharges.

Although Skyworks offerings in Barcelona favored reduced size over the highest level of amplifier convergence, it plans to place call time at the top of its 2009 priority list. "Even more than size and integration, people want to see better battery life and extended call time," explained Greg Waters, Skyworks general manager of front-end solutions. "Over the next 12 months you re going to see very dramatically improved talk time from Skyworks."

Much discussion at the MWC centered on 4G standards, with the GSM Association-sponsored LTE protocol grabbing many headlines. US telecoms firm Verizon unveiled a roadmap for LTE deployment in 2010, as well as the equipment vendors that it has chosen to support the rollout. Subsequently, Skyworks and Anadigics laid claim to providing PAs for the only high-profile prototype LTE handset on show in Barcelona, produced by LG.

RFMD and TriQuint concede that the frequency set to carry LTE signals initially, 2.5 GHz, is too far away from the frequencies of existing standards to include in their converged architectures. So, even when their more-integrated products hit the market, the early mobile devices aimed at LTE are likely to have PAs "bolted on" for the 4G standard.

Skyworks major promotion at the MWC revolved around two PA modules and four front-end modules targeted at LTE in the 2.5 GHz band. In contrast, RFMD, although working in this area, believes that it s too early to unveil its technologies. And even though his company has already introduced its first products in this area, Skyworks Waters agrees that changes are likely to be seen in the implementation of LTE, sooner rather than later. "It will become part of the wideband CDMA waveform," he predicted.

This close relationship between bands will be exploited by Anadigics in its effort to address 4G standards. "We have found that many of our existing UMTS products [addressing standards such as wideband CDMA] are suitable for LTE," explained Bruce Webber, Anadigics director of marketing for wireless products. His company s wireless design team is working with what Webber calls "solid partners" who are involved in the standard-setting process. These partners will advise Anadigics on how best to make its existing products most suitable for LTE. "We re relying on them for some guidance on what they need in a power amplifier," Webber said.

At the MWC, Anadigics launched a PA that covers the whole frequency region from 2.3 to 2.7 GHz, suitable for LTE and the more-immediate WiMAX 4G standard. Major WiMAX backer and Anadigics customer Intel made much of the 135 commercial deployments that its 4G standard has seen. While truly mobile WiMAX will only begin to make an impact this year, its ability to provide broadband in countries with poor telecommunications infrastructure is an example of the power of wireless technologies. It s this underlying power that has helped to keep the MWC – in spite of the poor economic situation – a vibrant event, and will continue to sustain GaAs firms through the recession.   

View pdf of article