Power Amp wars begin for 5G

Written by Mark LaPedus for Semiconductor Engineering – Companies are working with different materials and approaches in different regions.

Demand is increasing for power amplifier chips and other RF devices for 5G base stations, setting the stage for a showdown among different companies and technologies.

The power amplifier device is a key component that boosts the RF power signals in base stations. It’s based on two competitive technologies, silicon-based LDMOS or RF gallium nitride (GaN). GaN, a III-V technology, outperforms LDMOS, making it ideal for the high-frequency requirements for 5G. But GaN is expensive with some challenges in the fab. And LDMOS (laterally-diffused metal-oxide semiconductor) has some limitations, but it isn’t going away.

Nonetheless, 5G is a fast-moving but complex market. In just one part of the supply chain, device makers manufacture RF chips like power amplifiers in fabs. From there the devices are shipped to base station vendors for integration. A so-called macro base station is a system located at a cell tower, which provides RF wireless coverage over a wide area.

Generally, the power amplifier device for previous-generation 3G base stations were based on LDMOS. LDMOS, a mature and inexpensive technology, took the early lead in the 4G base station market. Over time, GaN power amps made significant inroads in 4G, at the expense of LDMOS. Power amplifiers are small circuits that convert a low-power RF signal into a higher power signal in base stations and other systems. The power amplifier isn’t the only device in the base station. These other devices are based on various processes.

Nonetheless, GaN-based power amps also are gaining steam in 5G. As in 4G, China’s base station vendors are adopting GaN-based power amp devices for their initial deployments of 5G systems in China. Other base station vendors are following suit.

There are several reasons for that. 5G, a next-generation wireless technology that’s faster than today’s 4G, is being deployed in two different areas – sub-6GHz and mmWave (28GHz and above). Generally, at higher frequencies, LDMOS runs out of steam, prompting the need for GaN. Compared to LDMOS, GaN has higher power densities and operates over a much wider frequency range.

“The need for dense, small-scale antenna arrays in 5G infrastructure is resulting in key challenges around power and thermal management in RF systems. With their improved wideband performance, efficiency and power density, GaN devices offer the potential for more compact solutions that can address these challenges,” said David Haynes, managing director of strategic marketing at Lam Research.

LDMOS isn’t going away, though. Some mobile operators are deploying both low- and high-frequency bands for 5G. LDMOS is suited for the lower bands. So both GaN and LDMOS will find a place in 5G. “In macro stations, GaN has gradually been taking market share from LDMOS following its wide adoption in Huawei’s 4G LTE infrastructure equipment,” said Ezgi Dogmus, an analyst at Yole Développement. “In the sub-6GHz regime in 5G we see tough competition between LDMOS and GaN in lower-power active antenna systems. GaN is being adopted in bands where large bandwidth capacity is needed.”

Regardless, the numbers are staggering. The total GaN RF market will increase from $740 million to more than $2 billion by 2025, with a CAGR of 12%, according to Yole. Telecom infrastructure and military radar are the main drivers for RF GaN. In another example, China built 130,000 5G base stations in 2019, with plans to install 500,000 more in 2020, according to Handel Jones, chief executive of IBS. By 2024, China’s goal is to deploy 6 million systems, Jones said. Japan, Korea, the U.S. and others are also making a big push in 5G… Full article