The Evolution of GaN: from Defense Applications to 5G
by Scott Vasquez, Senior Market Strategy Leader – Qorvo
As gallium nitride’s advantages (increased power density and efficiency, and improved thermal properties that enable higher reliability and operating temperature) are becoming increasingly cost-effective, the technology is no longer considered exclusive to defense programs such as electronic warfare and jammers.
Plastic packaging technologies are just one way GaN is becoming more accessible — and critical — for commercial applications like next-generation wireless infrastructure to deliver on the ever-increasing demands for data faster, and to more places.
GaN is an efficient, wide-bandgap, reliable PA technology making year-over-year strides toward network efficiency. GaN offers superior properties of high power density, power-added efficiency (PAE), gain, and ease in impedance matching, which improves overall efficiency in the RF chain. By starting with a fundamentally better semiconductor technology, performance targets can be achieved at vastly improved energy efficiency.
Over the last few years, device packaging technology has been a key factor in the alignment of GaN costs with market volumes. The availability of high-power GaN MMIC power amplifiers in small, lightweight plastic packages improves the size, weight and power (SWaP) performance for a range of commercial applications — optimizing system performance at a competitive price point.
For broadband cable, GaN is being employed in DOCSIS 3.1 upgrades. At Qorvo, our multi-chip-module innovations are accelerating the deployment of high-speed broadband networks while providing cable designers greater flexibility in product design. These modules, along with thermal sensing pins and advanced GaN on SiC integration capabilities, enable CATV product designers to significantly lower costs, increase bandwidth and reduce board space by as much as 50 percent. Multi-system operators (MSOs) can leverage these GaN packaging and integration innovations to upgrade equipment within existing product footprints, saving installation time and cost while enhancing performance.
GaN with advanced packaging technologies is already being deployed in commercial wireless infrastructure applications such as small cell and cellular base stations.
Next up for GaN? It is poised to be a critical technology for 5G and next-generation wireless infrastructure.
Scheduled for commercial launch in 2020, 5G is expected to offer significant advantages, including higher capacity and efficiency, lower latency, and ubiquitous connectivity.
In telecom networks, much of the network energy consumption comes from the RF chain. GaN’s superior properties of high power density, PAE, gain, and ease in impedance-matching improve overall efficiency within the RF chain.. The introduction of GaN in the base transceiver station (BTS) ecosystem provides a sharp increase in front-end efficiency, making it a new go-to technology for both high- and low-power applications.
The build-out of 4G LTE networks is maturing, but there are many upgrades that will bridge the gap to 5G. We currently are in the 5G definition and proof-of-concept phase, but companies like Verizon are accelerating the timetable for early deployments focused on fixed-wireless access.
Early 5G trials began in 2013, and data from these and more recent experiments are now frequently published. Qorvo continues to build on our 30 years of GaN for both commercial and defense system integration work. We are engaged with 5G service providers and OEMs worldwide, supporting the evolving 5G ecosystem and helping accelerate the deployment of 5G by supporting more than twenty 5G trials over the last year.
Key technologies offering promising results in mmWave, massive Multi-input Multi-output (MIMO) antenna arrays, and beamforming are already in pre-commercial development. All of the base station OEMs are in the product trial mode. Companies like Qualcomm and Intel are testing 5G-enabled modems, such as the X50 modem, which works in the 28 GHz band.
GaN for Massive MIMO Applications
Leading cellular operators are enhancing wireless spectrum efficiency and boosting network capacity by more than 500 percent by adopting technologies including massive MIMO, Active Antenna Systems (AAS) and LTE-Pro.
Qorvo and NanoSemi have published demonstration data on ultra-wide linearization of GaN power amplifiers for massive MIMO applications.
Qorvo’s QPA2705 is an integrated GaN driver and GaN Doherty power amplifier with 30 dB gain, P3dB of +44 dBm, PAE of 35 percent at +37 dBm average output power in a compact 6x10mm surface mount package. Using the QPA2705 with NanoSemi’s proprietary digital compensation algorithms achieved impressive results, shown in Table 1. This superior performance enables operators to implement highly efficient, small form-factor massive MIMO transceivers for next-generation base stations.
NanoSemi and Qorvo have also demonstrated linearization of the QPA2705 cascaded Doherty driver amplifier and QPD2730 dual-channel GaN Doherty PA final stage with -58 dBc for 60 MHz LTE signals, and -55 dBc for 100 MHz LTE signals.
5G Diversity and Balance
Forward-looking companies are dialing-in major 5G system architectures, frequency bands, and enabling technologies to find the proper balance of cost, performance, and complexity.
To meet the diverse set of 5G requirements, GaN manufacturers need to offer several variations that span a broad range of frequencies and power levels. With more than one GaN process to choose from, a designer can optimally match a GaN technology to an application. The graph below examines Qorvo’s capabilities in this realm.
As Qorvo is guiding standards bodies and working with the world’s top mobile carriers on next-generation networks, we are also using our early lead in network infrastructure to help architect solutions for next generation devices for use in these networks.
Other 5G Applications
With properties including operating in high-temperature environments, GaN is well suited for many different applications, from passively-cooled, all-outdoor tower-top base station electronics to automobile applications and cable boxes. Having a wide array of GaN technology choices will mean more applications being serviced throughout the world, and Qorvo is well positioned for this technology transition.
Scott Vasquez is a senior market strategy leader at Qorvo, a provider of RF solutions.