BARCELONA — STMicroelectronics, not among the “usual suspects” indulging in 5G chips, is nonetheless making its move into this nascent market.

ST’s approach to 5G opportunities is cautious but methodical. First up, it’s going to advance its collaboration with Macom (Lowell, Massachusetts) on GaN-on-silicon, focusing initially on the telecom base-station market. Separately, ST is also angling to develop solutions for repeaters and small cells, which are sorely needed in 5G mmWave networks.

The newly announced agreement with Macom calls for ST to expand its 150-mm GaN-on-silicon production capacity this year at fabs in Catania, Sicily, and possibly move to 200 mm as demand picks up. GaN-on-silicon — instead of the GaN-on-SiC promoted by competitors — will be critical for OEMs to build out a new generation of high-performance 5G networks, according to Macom. It can offer “better performance and cost,” and now that a deal with ST is in place, GaN-on-silicon can provide a “high-volume supply chain,” according to the company.

GaN Performance GaN Performance — Cost — Scalability (Source: Macom)

Macom, targeting a more than 50% share in the base-station market, is hoping to “have capabilities to service up to 85% of the global 5G network buildout,” John Croteau, president and CEO of Macom, said in a statement.

During ST’s presentation at Mobile World Congress this week, Marco Monti, president of ST’s automotive and discrete components group, expressed ST’s similarly strong commitment to GaN-on-silicon.

When demands for GaN-on-silicon expand further — including mobile — Monti said that ST is ready to move forward with “double-sourcing.” This will team Catania 8-inch and Singapore 8-inch fabs for flexibility and extra volume.

ST is scaling GaN-on-siliconGaN-on-silicon manufacturing capacity for broader opportunities. (Source: ST Microelectronics)

Beyond being a foundry

Macom has a small fab of its own, but it needs ST as a strategic partner to achieve its own ambitions. The GaN-on-silicon expansion is believed to involve joint investment from both companies, but neither are disclosing financial arrangements.

Under the deal, ST provides Macom with foundry service, with base-station chips from ST fabs sold as Macom ICs. But there are more layers to the partnership, according to ST. On one layer, ST licensed Macom’s IP on GaN-on-silicon manufacturing. On another layer, ST is closely working with Macom on GaN-on-silicon chip designs.

The collaboration opens the door for ST to use GaN-on-silicon technology in market segments that do not appeal to Macom. For example, ST might develop GaN-on-silicon chips for automotive in the medium-term future.

During ST’s analyst/press event here, ST also alluded to its potential interest in developing GaN-on-silicon RF power amplifiers for handsets.

Although a mass market opportunity for 5G handsets may not arrive until well into the 2020s, ST believes that GaN-on-silicon has a “huge cost advantage” compared to traditional GaAs and its competitors’ GaN-on-SiC. ST has initiated discussions with “key market players,” according to its presentation.

STMicroelectronics handset

5G mmWave repeaters, small cells

At Mobile World Congress, ST teased its upcoming announcement about getting into the 5G mmWave network infrastructure market. While details remain sketchy, Claude Dardanne, president of ST’s microcontrollers & digital ICs group, discussed how ST’s internal expertise — accumulated from past experience in the set-top box and satellite communications businesses — can be applied to 5G mmWave.

He stressed, “I am not talking about sub-6 GHz, but 5G mmWave.” Since mmWave is a new spectrum that relies on such new technologies as advanced beamforming and massive MiMO, its network architecture will become much denser, demanding many small cells, he explained.

In illustrating ST’s strength, Dardanne pointed out:

  • ST’s wide range of RF technology solutions including BiCMOS, CMOS, FD-SOI, and RF-SOI
  • ST’s high-performance mmWave RF solutions offering RF transceiver products up to 60 GHz
  • ST pioneered beamforming solutions for the satellite communication market, including RF front-end (PA, LNA), transceiver, and beamforming products

Pressed for more details, ST declined to comment, but the announcement appears slated for May.

ST’s place in 5G

Observers of ST remain skeptical as to how much expertise, or “corporate will,” is left within ST to really get back into the mobile business.

Jim McGregor, principal analysts at Tirias Research, told us, “I think you have to qualify ST’s position. ST is a broad company in many markets with a variety of discrete analog and digital components. So I would envision ST being part of the solution for power, RF, and maybe even control through their MCUs or ASICs.” He added, “They have long had components in these areas, so extending into the mmWave arena is not a surprise.”

Loring Wirbel, a telecommunications analyst, told EE Times that despite ST’s well-accepted STM32 cores, “ST just didn’t have the integration expertise to combine baseband with existing power amp and transceiver discrete to enter the [mobile phone] market — at least so far.”

He added, “From afar, I considered ST to be analogous in some ways to Texas Instruments — pruning back the business to strengths like automotive, sensor/MEMS, IoT, and general mixed-signal while phasing out ST-Ericsson wireless, set-top boxes, etc.”

That said, Wirbel pointed out, “I would say that the set-top business’s expertise in satcom, combined with ST-Ericsson full-integration chipsets re-purposed for higher frequencies, could give ST a good war chest in theory for entering 5- to 60-GHz and dedicated 60-GHz markets.”

Considering that ST’s base of expertise is mostly IP and patents and the bulk of its former staff is gone, Wirbel wonders how willing ST is to scale up both design engineering and product marketing to compete effectively in the cutthroat handset market.

Wirbel put more stock in ST’s announced pact with Macom in GaN-on-silicon. He noted, “Macom has some excellent mixed-signal designs of physical transceivers and amps in both millimeter wave and optical.”

The early stages of a commercial millimeter-wave market for backhaul have featured high-frequency analog designs from startups like Blu Wireless, Peraso, and Hittite/Analog Devices, according to Wirbel. “There are some early moves to more integration from Broadcom, Qualcomm, and Intel, but I think the giants are all at early stages.”

In summary, Wirbel noted, “ST has great transceiver and power amp designs, and excellent foundry, for the [5G] market, and it would have the time to develop designs to compete with biggies like Broadcom.” But for now, ST will have to take baby steps by relying on deals like the MACOM pact to enter the 5G market.

GaN-on-silicon vs. GaN-on-SiC While both Macom and ST appear confident about the future of GaN-on-silicon, not everyone agrees. Market and technology research firm Yole Développement, for example, is taking a more measured view.

Click here for larger image
(Source: Yole Developpement)

Click here for larger image

(Source: Yole Développement)

Hong Lin, senior technology & market analyst at Yole, told EE Times, “Specification of 5G is evolving very quickly. Plenty of solutions are competing for 5G mmWave, and those different products are under qualification.” The analyst believes that it is still too early to presume the shape of things to come.