Senior Signal Integrity Engineer

You will own signal integrity end to end — from silicon package, through the board, to the system channel. Senior IC role with architectural influence: you won't be handed a closed spec to verify, you'll help define it. What you will work on: • Full-wave extraction and SI closure for a multi-die AI accelerator package • PCIe Gen6 (PAM4) channel design and compliance margining • LPDDR6 interface design, timing budget and bus-level closure • SI ownership on a rack-scale system: backplane, connectors, cabling and interconnect Responsibilities: • Budgets & feasibility: Define and hold loss, crosstalk and jitter budgets across die, package, board and channel. Run pre-layout feasibility studies that shape escape routing, stackup and layer assignment before layout is committed. • Extraction & simulation: Perform 3D full-wave and hybrid extraction of package and board structures, defining port and reference conventions. Run statistical and time-domain channel simulation with IBIS-AMI, interpreted FEC-aware for Gen6. • Model quality: Own passivity, causality, reciprocity and DC accuracy gates on every model entering the flow. • Vendor & validation: Define SI requirements in package vendor and OSAT statements of work. Drive model and characterisation requirements with IP, PHY, DRAM and package vendors. Correlate against VNA, TDR and on-die margin scans, and support board bring-up. Requirements: • 8+ years in signal integrity for high-speed digital systems, including package-level work • Hands-on with at least one 3D EM extraction suite — Ansys HFSS/SIwave, Cadence Clarity/Sigrity, Keysight or equivalent • Proven closure on a multi-gigabit SerDes (PCIe Gen5/Gen6 or comparable) and a wide parallel memory interface (DDR5, LPDDR5/6 or HBM) • Working knowledge of IBIS, IBIS-AMI and channel simulation methodology • Comfortable reading a package substrate stackup and bump map, and reasoning about what the physics will do • Python scripting for automation and post-processing Nice to Have: • Silicon package co-design — 2.5D, interposer, chiplet or advanced substrate • Material characterisation and measurement correlation • Familiarity with OCP rack-scale platforms and high-speed connector systems • Automated or AI-assisted engineering flows — PyAEDT, scikit-rf or similar Why Semidynamics? • Work for one of Europe’s most promising deep-tech semiconductor scale-ups. • Accelerated development path. • 4 days per week in the Barcelona office (city center), 1 day WFH. • 1 week of work from everywhere in the world. • Competitive package. • A collaborative, technical, and growth-oriented environment that values direct ownership and clear thinking.