Qualcomm’s new “RF360” family of RF front-end cellphones products includes multiband, multimode CMOS power amplifiers capable of transmitting LTE signals as well as 3G and GGE, previously the exclusive domain of GaAs-based PAs. Shipments of GaAs-based multimode, multiband PAs (MM-PAs) have grown rapidly over the past three years primarily in smartphones with more than four linear (3G / 4G) bands, for example in the Apple iPhone 4S. The announcement can be construed as a direct challenge to the GaAs industry, which relies on cellular PAs for over half of its GaAs product revenues.
Qualcomm has entered the market for MM-PAs by drawing on the benefits of envelope tracking (ET), a new technology that improves PA efficiency. ET, whether used in conjunction with CMOS or GaAs PAs, is expected to ship in cellphones in volumes within the next 12 months, and its viability will prove crucial to the success of CMOS PAs, which last year accounted for less than 10 percent of the cellular PA market in unit terms.
As most silicon-based semiconductor veterans say, “If it can be done in CMOS, eventually it will” to paraphrase the common sentiment. To back this up, some will recall the rapid ouster of GaAs from radio transceivers in CDMA phones a decade ago, or the quick transition from GaAs p-HEMT to CMOS SoI in RF switches in mobile phones now well underway. However, GaAs-based PAs are extraordinarily linear and efficient, and GaAs PA suppliers have driven costs down for more than a decade, producing more than 3 billion PAs in 2012 alone. In addition, the top GaAs-based PA suppliers offer complete front-end solutions that include small-footprint PA-switches, PA-duplexers, switch-filter modules and duplexer-switch modules.
The leading GaAs PA suppliers Skyworks, RFMD, TriQuint, Avago Tech and Murata have not hit the panic button over CMOS. In comparison to GaAs, CMOS MM-PAs with ET are new and unproven, and far from optimum, as pointed out by early performance results gleaned from OEMs sampling Qualcomm’s first CMOS PAs. Today, GaAs PAs still beat CMOS in terms of linearity-efficiency, even with ET, and it will probably take Qualcomm and other CMOS PA suppliers several years to improve the technology and gain unqualified acceptance by OEMs, who are extraordinarily conservative with new technologies, even those from major players such as Qualcomm.
This does not mean the death of GaAs, but the Qualcomm announcement undoubtedly signals faster acceptance of CMOS PAs. To stay competitive, GaAs PA suppliers will have to continue to innovate, and they may also need to offer their own CMOS PAs for the most cost-sensitive phones, as Skyworks and RFMD have already done.
For more about this topic, Eric Higham, Director of the Strategy Analytics GaAs and Compound Semiconductor market research service will host a panel discussion at the upcoming IEEE International Microwave Symposium titled “Death of GaAs?” You are welcome to attend. This will be held Thursday, June 6th from 12:00 – 1:20 PM in Seattle, WA (room location TBD).
You can also read more in-depth analyses if you are a Strategy Analytics RF & Wireless Components subscriber in the following new reports, or contact Christopher Taylor at ctaylor@strategyanalytics.com with questions:
Qualcomm Challenges GaAs PA Suppliers with CMOS PAs and Complete Front-end Subsystems, March 2013.
PA Market in Flux: CMOS PAs and Envelope Tracking Emerge as Major Themes at MWC 2013, March 2013.