Analog Mixed Signal Design Engineer

The Role

We’re searching for a Senior/Staff Analog Design Engineer to architect, design and bring to production ultra‑high‑speed (> 20 GHz analog bandwidth, > 40 GS/s) CMOS ADCs and DACs that directly interface with our optical compute fabric.

Success in this role requires mastery of low‑jitter sampling circuits, broadband front ends, and calibration techniques that deliver outstanding ENOB and power efficiency. The ideal candidate will have a strong background in electrical engineering and semiconductor physics, along with a passion for developing reliable, high-performance analogue circuits that drive breakthrough AI hardware.

Responsibilities

Define converter architectures that will deliver on the target of Analog bandwidth > 20 GHz.

Design critical high‑speed building blocks: bootstrapped or switch‑linearised T/H, low‑skew clock trees (< 50 fs rms aperture jitter), broadband input buffers, thermometer and binary‑weighted current cells, dynamic element matching (DEM) and background calibration loops.

Model and close performance using transistor‑level and behavioural co‑simulation (SpectreRF / AFS RF Verilog‑A/AMS), then drive post‑layout extraction, EM/IR and thermal analysis to achieve first‑silicon success.

Collaborate with packaging, SerDes and PLL teams to co‑design I/O impedance, ESD, supply isolation and on‑interposer routing so converters integrate cleanly into multi‑lane fabrics.

Lead silicon bring‑up: on‑wafer static and dynamic tests, high‑speed digitiser / AWG measurements, DNL/INL, static‑power and jitter transfer characterisation; oversee production test pattern generation and built‑in self‑test (BIST) hooks.

Mentor junior engineers, conduct rigorous design and layout reviews, and publish internal app‑notes to disseminate best practices for GHz‑class data‑converter design.

Track and inject into the team the latest advances in time‑interleaving calibration, background mismatch correction, supply‑noise tolerant reference generation and layout techniques.

Skills & Experience

7 years of production CMOS data‑converter design, with at least two tape‑outs running ≥ 20 GHz analog bandwidth.

Deep knowledge of track‑and‑hold linearity, aperture‑jitter minimisation, current‑steering DAC glitch energy reduction, capacitor and device matching, and metastability‑hard comparators.

Proficiency with industry EDA flows: Cadence Virtuoso, SpectreRF / AFS RF, Verilog‑A/AMS, EMX / HFSS for package on‑chip inductor modelling, and mixed‑signal verification.

Demonstrated ability to achieve < 100 fs rms aperture jitter, < 0.5 LSB DNL/INL (post‑calibration), and low‑ppm clock‑to‑data skew in silicon.

Experience incorporating digital calibration engines (DSP or µ‑controller‑driven) for offset, gain, timing and element‑mismatch correction.

Solid grasp of supply‑noise coupling, substrate isolation, ESD, latch‑up, and advanced‑node layout techniques (double patterning, EUV constraints, local interconnect).

Strong lab skills: high‑speed AWG/BERT operation, FFT‑based dynamic testing, de‑embedding, and scripting (Python / MATLAB) for data reduction.

Bachelor’s degree in Electrical Engineering or related field (Master’s / PhD preferred).

Excellent communication, cross‑disciplinary collaboration, and a demonstrated ability to execute quickly in innovation‑driven environments.

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.