Senior Staff Analog Mixed - Signal Design and Modelling Engineer

IonQ, Inc . [NYSE: IONQ] is the world's leading quantum platform and merchant supplier - delivering integrated quantum solutions across computing, networking, sensing, and security. IonQ's newest generation of quantum computers, the IonQ Tempo, is the latest in a line of cutting-edge systems that have been helping customers and partners including Amazon Web Services, and AstraZeneca achieve 20x performance results and accelerate innovation in drug discovery, materials science, financial modeling, logistics, cybersecurity, and defense. In 2025, the company achieved 99.99% two-qubit gate fidelity, setting a world record in quantum computing performance . Oxford Ionics, now part of IonQ, is pioneering the next generation of quantum computing. Using our world-leading trapped-ion technology, we're building the most powerful, accurate and reliable quantum systems to tackle problems that today's supercomputers cannot solve. Joining Oxford Ionics means becoming part of a global IonQ team that is transforming the future of quantum technology - faster, at scale, and with real world impact. Headquartered in College Park, Maryland, IonQ has operations in California, Colorado, Massachusetts, Tennessee, Washington, Italy, South Korea, Sweden, Switzerland, Canada, and the United Kingdom. Our quantum computing services are available through all major cloud providers, while we also meet the needs of networking and sensing customers across land, sea, air, and space. IonQ is making quantum platforms more accessible and impactful than ever before. What to expect: We are looking for a Staff Analog Mixed-Signal Design and Verification Engineer to join our Cryo-CMOS IC team at IonQ Oxford. In this role, you will design analog and mixed-signal blocks from specification through circuit design, simulation, layout, tape-out and silicon validation. You will also own top-level chip integration and modelling as a first-class part of our Cryo-CMOS development flow. In this you will build and maintain the model of the chip that the whole team simulates against, a mixed-abstraction model combining transistor-level circuits with Verilog-A/Verilog-AMS and SystemVerilog real-number behavioural blocks. You will decide which blocks are represented at which level of abstraction, keep the models faithful to the schematics and measured silicon. The full-chip model will then be used to verify the ASICs that control the quantum processor from room temperature down to a few kelvin. You'll play an important part in shaping the design, modelling and verification methodology, standards and sign-off criteria that support our work in building the world's most advanced quantum systems. What you'll be responsible for: In this position, you will build and maintain the model of the chip that the whole team simulates against, a mixed-abstraction model combining transistor-level circuits with Verilog-A/Verilog-AMS and SystemVerilog real-number behavioural blocks. These models will be derived form first-principles mathematics and correlated against schematic and measured silicon. You will decide which blocks are represented at which level of abstraction, keep the models faithful to the schematics and measured silicon. The full-chip model will then be used to verify the ASICs that control the quantum processor from room temperature down to a few kelvin. You'll have the opportunity to set the design and modelling standards the programme signs off against, making trusted models to inform tape-out decisions, and raise the design and modelling capability of the engineers around you, contributing directly to the success of IonQ's quantum computing roadmap. Key responsibilities include:

• Own the full-chip modelling strategy: model architecture, abstraction levels, accuracy targets and sign-off criteria used across the IC development flow
• Owning analog and mixed-signal blocks (references, DACs, switches, regulators, clock distribution) from specification through schematic design
• Own top-level integration: define block interfaces and specifications, assemble the top level, and run the full-chip mixed-signal simulations that verify the ASIC Develop Verilog-A and Verilog-AMS models of analog blocks and assemble them into a simulatable full chip
• Build real-number models so the full chip runs in digital verification and regression at practical speed
• Derive models from mathematics: turn a transfer function, a Z-parameter network description or a MATLAB analysis into robust Verilog-A with well-behaved tolerances
• Define and run model-versus-schematic correlation, keeping models in sync with design releases, and feed measured silicon behaviour, back into the models and the block designs
• Stand up mixed-signal co-simulation and regression (Cadence AMS Designer, Xcelium with Spectre) Lead block-level design reviews and mentor engineers on circuit design and modelling craft What you'll need: To be successful, you will need deep analog and mixed-signal design and modelling experience, typically 10+ years. You will have designed blocks proven in silicon and models and used in production tape-out flows. You will bring expert transistor-level design of precision analog blocks (references, DACs, regulators, switches, clock distribution) taken through PVT and Monte Carlo, layout and silicon validation, together with expert Verilog-A and Verilog-AMS and strong real-number modelling. You'd be a great fit with:
• Multiple tape-outs with responsibility for block design and top-level integration, including silicon bring-up and bench characterisation
• Strong mathematical foundations: linear systems, Laplace and z-domain analysis, network (Z-) parameters, noise and non-linearity
• Fluency in a production Cadence flow: Virtuoso, Spectre, Xcelium and AMS Designer or similar co-simulation environments, including parasitic extraction and post-layout sign-off
• SystemVerilog, plus MATLAB or Python/NumPy for analysis and model validation; scripting to automate model generation, checking and regression
• Cryogenic, space or other extreme-environment silicon experience will be highly beneficial, especially designing beyond foundry model validity using measured device data We're looking for someone who can design a block to specification and model it at the right fidelity, derive a model from equations and implement it end to end. You should be able to judge what to model and at what abstraction, align designers, verification and systems engineers on what a model does and does not promise, and contribute effectively within a fast-moving, highly technical team. So why us? Be part of a team that's shaping the future of quantum. We offer more than just a role, you'll join a world class community of scientists, engineers and innovators working to unlock the full potential of quantum computing. We offer a range of benefits, including opportunities to further your career alongside industry leaders, a competitive salary with IonQ stock options, an annual performance bonus, generous annual leave, flexible hybrid working, private medical and dental insurance for you and your family, and much more. Join us and be part of the future of quantum computing.