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SiFive Forms Business Unit to Build Chips With RISC-V and Arm Inside

Aug. 21, 2020
SiFive said the business unit, called OpenFive, would work with customers to manufacture chips based on the 5-nanometer node or less advanced foundry processes as well as 2.5D advanced packaging.

SiFive, a Silicon Valley startup, is retooling its custom chip design division as it looks to challenge Arm’s dominance in the chip business with RISC-V technology and lure more of the electronics space to open-source semiconductors.

On Monday, the company said it would set up a business, called OpenFive, to oversee its custom system-on-chip services. SiFive said it would work with customers to create chips for areas ranging from artificial intelligence in data centers to Internet of Things devices and that it would use the processor cores ideal for the job. It plans to use RISC-V cores, rival Arm cores, or both in a single product, to design chips for its customers.

SiFive is one of the leaders in the market for chips based on the RISC-V architecture, which can be accessed by anyone at no cost. SiFive licenses out the blueprints to its RISC-V cores and other system-on-chip building blocks for other companies to use in actual chips—and then it reaps royalty fees from its customers. RISC-V is an instruction set architecture (ISA) and it serves as a playbook for designing a computer chip.

One of the advantages is that anyone can add custom features to RISC-V cores and further differentiate them with custom sets of instructions. But designing chips from the ground up based on the RISC-V ISA can be costly and require years of development. SiFive is trying to reduce costs and the time-to-market by rolling out ready-to-use cores and intellectual property (IP) and licensing them out to companies that assemble them into chips.

Arm controls the CPU instruction set at the heart of its proprietary architecture, which is used in almost all of the world's smartphones and licensed by everyone from Apple to Nvidia. It generally prohibits anyone from adding new sets of software instructions to its chips.

SiFive has also rolled development tools that are used to add custom features to its cores, ranging from more on-chip memory to more interfaces. It also supplies tools to add custom instructions to the RISC-V cores. Customers use other tools to assemble the CPU cores and other IP into final products. It also sells development boards that feature its RISC-V cores, which compete against Arm's Cortex-A, Cortex-M, and other cores.

The company also volunteers to build out custom chips, including SoCs and ASICs, for any customers without an internal semiconductor division. It also works with TSMC and other foundry partners to start manufacturing the chips, which could include Arm cores. On Monday, SiFive said it was moving all its custom chip design operations into OpenFive. That gives it more freedom to focus on developing its RISC-V CPU cores, the firm said.

SiFive is trying to persuade more companies to follow the footsteps of Google, Apple, Amazon, and other Silicon Valley giants in building more of the chips they used to buy for data centers, smartphones, and other areas. Moore’s Law has been the electronics industry's playbook for decades, leading to the development of smaller, cheaper, and faster chips over time. But the pace of these performance leaps has slipped in recent years.

"The world is moving towards domain-specific architectures to solve the needs of power, performance and cost”, said Shafy Eltoukhy, senior vice president and general manager of OpenFive, which plans to operate independently. "Working collaboratively with our partners and customers, OpenFive innovates with segment-specific silicon solutions based on optimized processors and SoC IP targeted to our customers' requirements."

SiFive has been crafting custom chips since it agreed to acquire contract chip vendor Open Silicon and its roughly 250 employees in 2018. SiFive said OpenFive, including the operations of Open Silicon, has rolled out more than 350 chips with cores based on Arm and other chip architectures. The company said that more than 150 million chips based on its designs have been manufactured over the 15 years.

"OpenFive will accelerate the adoption of domain-specific silicon designs for workload-focused performance," said Naveed Sherwani, chief executive of SiFive and one of the founders of Open Silicon over 15 years ago. Giving customers the ability to add open and proprietary architectures to the same chip could push more chip vendors to use RISC-V cores in new hardware, he said. Open Silicon has partnered with 150 customers.

SiFive said the business would give customers the ability to manufacture chips with the 5-nanometer node or less advanced foundry processes as well as 2.5D advanced packaging.

OpenFive said customers can choose blocks of technology from its component library. The portfolio includes its low-latency, high-throughput interconnect fabric; 400G and 800G Ethernet IP for data centers and networking; USB subsystem IP for consumer and IoT devices; and die-to-die interconnect IP for assembling new products out of chiplets. SiFive has RISC-V cores spanning server processors to tiny, power-sipping cores.

Last month, the company rolled out major upgrades to its RISC-V processing cores that it said would increase overall performance as well as reduce die area and power consumption.

SiFive said this month that it pulled in more than $60 million in its latest funding round, led by memory chip vendor SK Hynix with investments from Qualcomm, Intel, Western Digital and other current investors. SiFive is gaining ground in the global chip business. Last year, it counted more than half of the world's top 10 semiconductor companies as its customers. The funding brings its total raised to $190 million since it was founded in 2015.

SiFive also introduced advanced trace and debug tools that can be paired with its processing cores to speed up the development of chips based on the RISC-V architecture.


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