Sphere Semi raises $20M to build AI-designed analog chips for defense and data centers

Summary

Sphere Semi has closed a $20M cumulative raise, adding a $12M round led by Acme Capital with Future Ventures as co-lead. The new capital layers on top of $8M previously raised from Construct, Abstract, Generational Partners, Village Global, and X Fund.

The company operates in analog semiconductors, a segment that represents roughly one-third of the global chip industry yet attracts far less attention than the GPU and CPU markets. Analog components underpin communications infrastructure, electronic warfare, and signals intelligence systems — markets where Sphere Semi has built its initial customer base.

The core differentiator is an AI engine that handles chip design end-to-end, from concept to fabrication-ready layouts. Analog chip design has historically been done by hand, unlike digital chips where automated layout tools are standard. Sphere Semi's platform generates hundreds of candidate designs with mapped performance characteristics, then works between customer and fabrication partner to deliver finished, packaged chips. The company operates as a fabless designer, outsourcing physical manufacturing.

Andoril is cited as a named defense customer, engaging Sphere Semi for analog front-end components in electronic warfare and SIGINT systems. The company is also forming a joint venture with one of the top-four U.S. defense primes, named only as a large contractor, to commercialize its RF component capabilities.

The next strategic move is mixed-signal chips for data center interconnect, the segment where Broadcom and Marvell have captured significant value since the AI infrastructure boom began. Mixed-signal components manage communication between GPUs and are a high-margin, high-volume market. Moving into that space requires more advanced fabrication nodes, which carry meaningfully higher unit costs, as well as significant hiring across chip design, software engineering, and AI engineering roles.