Senior Signal Integrity Engineer in London

Fractile is building silicon, systems and software which will redefine the frontier of AI: running the world's most advanced models at radically higher speed and lower cost. We have an exceptional team across hardware and software capable of bringing about this change, and we are growing fast to meet demand and deliver our product at scale.

We are seeking an experienced Signal Integrity Engineer to design, analyse and validate a high-density AI accelerator system destined for data centre deployment. The role covers the whole system, including the PCB layout for the Fractile Accelerators; high-speed cabling; power regulators; clocks and support microprocessors.

• Perform pre- and post-layout signal integrity analysis and simulations for high-speed digital interfaces such as DDR and PCIe, using industry-standard tools to ensure that the design meets the system level budget.
• Define Printed Circuit Board (PCB) stack-ups, routing strategies, and design rules to optimise signal quality and power delivery networks (PDN).
• Collaborate closely with hardware designers, PCB layout engineers, and mechanical teams to ensure design choices align with signal integrity best practices and meet all performance and reliability targets.
• Develop comprehensive test plans and perform hands-on validation and characterisation of prototypes in the lab using high-speed test equipment, including oscilloscopes, Vector Network Analysers (VNA), and Time Domain Reflectometry (TDR).
• Troubleshoot and resolve complex signal integrity and power integrity issues during the design, bring-up, and validation phases.
• Create and maintain detailed technical documentation, design guidelines, and test reports for cross-functional teams and external partners.
• Stay updated on the latest signal integrity technologies, industry standards, and emerging trends to drive continuous improvement in design methodologies.

• Diploma, Bachelor's degree in Electrical Engineering, Electronics Engineering, or a related field, or equivalent practical experience.
• At least 7 years of experience in hardware design with an emphasis on signal integrity analysis and high-speed PCB design.
• Proven experience working with high-speed digital and high-power system designs.

• Strong understanding of high-speed signal transmission principles, electromagnetic theory, and coupling mechanisms.
• Proficiency with signal integrity simulation and modeling software (e.g., Ansys HFSS, Cadence Sigrity/PowerSI, HyperLynx, ADS, or similar).
• Hands-on experience with lab equipment for SI measurements (oscilloscopes, VNAs, TDRs, etc.).
• Experience taking designs through prototyping, test, and production.
• Strong collaboration skills, comfortable working across disciplines and with suppliers.

• Experience with AI accelerator or HPC hardware.
• Experience with multi-phase Voltage Regulator Modules (VRMs).

• Ownership and execution: you will have full agency to drive your work forward.
• Rapid iteration: we all work directly with top leadership to move from idea to hardware on ambitious timelines.
• Full-stack engagement: hardware, software, silicon, and modelling teams all work closely together to create a product with generational impact.
• Optimistic and pragmatic: we possess the will to win, and to do the hard work to get us there.
• Team player mentality: the mission is bigger than any of us, and we have the curiosity and technical focus to see the best idea shipped, no matter whose it is.

• Founded in 2022, team of 70+, which is expanding rapidly.
• Modern, open offices in London and Bristol.
• Collaborative, problem-solving culture built on deep curiosity, entrepreneurial initiative and technical fluency.

Export control and security clearance: Certain roles may involve working on technologies subject to export restrictions. Applicants may be required to undergo additional eligibility checks to ensure compliance with applicable law.