Senior / Staff Digital Design Engineer

The Role

We are seeking highly skilled and motivated Senior/Staff Digital Design Engineers with a strong focus on CMOS digital design to take end‑to‑end ownership of high‑speed, real‑time data‑processing silicon—from early algorithm modelling to verified RTL and silicon bring‑up. You will join a multidisciplinary group creating next‑generation OTPUs where digital, optical and mixed‑signal domains intersect. The ideal candidate will have a strong background in electrical engineering and semiconductor physics, along with a passion for developing reliable, high-performance digital circuits that drive breakthrough AI hardware.

Responsibilities

• Architect, design and implement high‑throughput digital pipelines (multi‑GSPS input rate, continuous streaming data paths, deep pipelining and hand‑shaking) in advanced CMOS nodes.

• Prototype and iterate rapidly in FPGA (Xilinx/AMD, Intel, or equivalent): bring‑up real‑time demos, exercise high‑speed transceivers, and feed learnings back into the ASIC.

• Model algorithms and validate concepts in MATLAB/Simulink (or equivalent), ensuring functional equivalence through to gate‑level sign‑off.

• Own RTL development (SystemVerilog / Verilog / VHDL) including synthesis, static‑timing closure, formal and constrained‑random verification.

• Analyse power, performance and area (PPA); implement innovative techniques to achieve aggressive bandwidth‑per‑watt targets.

• Collaborate with optical‑hardware, mixed‑signal and software teams to optimise data‑converter interfaces, clock‑domain crossings and firmware abstractions.

• Mentor junior engineers, lead design reviews and champion best‑practice design methodologies.

Skills & Experience

• 7+ years of hands‑on digital design for high‑performance ASICs or SoCs, including ownership of at least one product that processes a continuous real‑time data stream.

• Proven success closing timing on multi‑hundred‑MHz to multi‑GHz clock domains and integrating high‑speed IP (e.g., SerDes, HBM/DDR, PCIe, 100 GbE or similar).

• Expertise with industry‑standard EDA flows: RTL synthesis, CDC/RDC, STA, power‑intent (UPF/CPF), lint, and gate‑level simulation.

• Demonstrated FPGA prototyping skills: constraint management, transceiver tuning, and hardware debug in the lab.

• Proficiency using MATLAB/Simulink or Python/NumPy for algorithm modelling, fixed‑point analysis and test‑vector generation.

• Solid grounding in digital signal‑processing concepts, computer‑architecture fundamentals and semiconductor device physics.

• Excellent communication and cross‑functional collaboration abilities; thrives in a fast‑moving, ambiguous environment.

Nice to have

• Tape‑out experience at 22 nm or below.

• Knowledge of coherent optical links or photonic‑electronic co‑design.

• Familiarity with AI/ML workloads, systolic arrays or tensor‑processing architectures.

• Contributions to open‑source RTL, verification frameworks or FPGA boards.

Compensation & Benefits

• $194,000 – $270,000, depending on experience, skills, and location.

• Competitive stock options, you're not just part of the journey, you will own a piece of it.

• Live within 45 minutes of the office? Perfect. Live within 20 minutes? We'll add an extra location bonus to your salary.

• We offer financial and operational relocation support (US and abroad), through a dedicated third-party provider who is on hand to make your move as seamless as possible.

• We offer visa sponsorship so if we make you an offer we will make every reasonable effort to secure you a visa, but we may not be able to sponsor visas for every role and candidate.

• We're in the process of setting up a US group policy once we have 5+ employees. In the meantime, we're providing a health insurance stipend of $800/month to offset costs. Once the group policy is live, Flux will cover 100% of the employee premium, and offer options like dental, vision and life insurance with an aim to remain competitive among Austin tech and start up employers.

• We offer US employees access to a 401(k) retirement savings plan and we plan to introduce an employer match in line with tech market norms (commonly in the 4-5% range). Our goal is to keep our retirement benefits competitive while we scale.

• Top of the line, high-spec tech for everyone.

• Sony noise-cancelling headphones and ergonomic setups to keep you comfortable and focused.

• Personal company card to spend on tools that help you do your job - like ChatGPT Pro or anything else that boosts your workflow.

• Periodic travel to London HQ and regular team socials.

• 33 days of paid time off (PTO), including US federal holidays.

Due to U.S. export control regulations, candidates' eligibility to work at Flux depends on their most recent citizenship or permanent residency status. We are generally unable to consider applicants whose most recent citizenship or permanent residence is in certain restricted countries (currently including Iran, North Korea, Syria, Cuba, Russia, Belarus, China, Hong Kong, Macau, and Venezuela). Applicants who have subsequently obtained citizenship or permanent residency in another country not subject to these restrictions may still be eligible

We do not accept unsolicited CVs from recruitment agencies, will not be liable for any fees, and prohibit unauthorised use of our company name in recruitment activities.