Clocking Architect
Job Details:
Job Description:
About Altera
At Altera™, our independence as the world’s largest pure-play FPGA solutions provider gives us the focus, speed, and agility to innovate without compromise. With more than four decades of industry-leading FPGA expertise, our singular mission is to deliver the programmable technologies that help customers differentiate, innovate, and scale across rapidly evolving markets like AI, cloud, networking, and edge. As an independent company, we move faster, invest deeper, and partner more closely-empowering our teams to drive breakthrough innovation and shape the future of the FPGA industry.
About the Role
Altera is seeking a highly experienced Clocking Architect to lead the definition, design, and integration of clocking architectures for its next-generation FPGA and SoC devices. In this role you will own the end-to-end clocking strategy - from subsystem clock planning through full-chip integration - ensuring robust clock delivery, minimal skew, and compliance with all functional and DFT timing requirements across a diverse set of high-speed protocols.
The ideal candidate brings deep hands-on expertise in PCIe, High-Speed Memory I/O, ARM, Ethernet, and SerDes clocking domains, combined with mastery of SDC constraint authoring for both functional and DFT modes. This is a high-visibility, high-impact role with direct influence over silicon architecture decisions.
Key Responsibilities:
Clocking Architecture & Full-Chip Strategy
Own and drive the complete clocking architecture for Altera’s FPGA/SoC devices, including clock tree topology, domain partitioning, frequency planning, and PLL/DLL resource allocation.
Define subsystem-level clocking plans aligned with chip-level power budgets, protocol timing margins, and physical implementation constraints.
Establish clock gating policies, low-power clocking methodologies, and dynamic frequency scaling strategies.
Deliver the clocking specification, clock architecture diagrams, and constraint management documentation as program-level deliverables.
Collaborate with RTL, physical design, timing, and verification teams to ensure the clock architecture is correctly modeled and implemented across all design stages.
Protocol-Specific Clocking Expertise
PCIe (Gen4/5/6): Define REFCLK, PCLK, and spread-spectrum clocking (SSC) architectures; support SRIS/SRNS topologies and PCIe reset/power management clocking sequences.
High-Speed Memory I/O (DDR5, LPDDR5, HBM2E/HBM3): Architect DFI clock, write leveling, read path, and DQS clocking to meet memory controller timing requirements.
ARM Subsystems (Cortex-A/M/R, DSU, CMN Interconnect): Own core, peripheral, and AMBA bus clock hierarchies; ensure compliance with ARM’s timing and power requirements.
Configuration Interfaces (eSPI, SPI, JTAG, LPC): Define boot and configuration clock domains, including secure boot and JTAG test clock isolation.
Ethernet (1G/10G/25G/100G/400G): Architect MAC, PCS, and PHY clock domains; support SyncE and IEEE 1588 Precision Time Protocol (PTP) clocking requirements.
SerDes (PCIe, Ethernet, Custom High-Speed I/O): Define lane CDR, TX/RX PLL, and gearbox clocking; address reference clock distribution and jitter budgets for multi-lane interfaces.
ML/AI Accelerator Clocking
Architect clocking solutions for FPGA-based and SoC-integrated ML/AI inference and training accelerator pipelines, including matrix multiply units, systolic arrays, and vector processing engines.
Define multi-frequency clock domain strategies for AI workloads: separate clock planes for compute fabric, memory subsystem (HBM/LPDDR), host interconnect (PCIe), and control path to maximize throughput and efficiency.
Own clocking for high-bandwidth AI memory interfaces (HBM2E/HBM3, LPDDR5X) used in AI inference cards and data-center FPGA overlays, ensuring sub-picosecond jitter budgets at peak bandwidth.
Support dynamic voltage and frequency scaling (DVFS) clocking architectures that adapt compute clock rates to AI workload demand and thermal headroom.
Collaborate with AI IP and compiler teams to align clock domain boundaries with dataflow partitioning, pipeline stage timing, and latency requirements of ML models.
Define clocking for on-chip AI accelerator interconnects (NoC, AXI streaming fabrics) and ensure CDC-clean handshaking between host, memory, and compute domains.
Clock Domain Crossing (CDC) Architecture & Verification
Own the full-chip CDC architecture plan: identify, classify, and document every asynchronous clock domain crossing from RTL inception through tape-out sign-off.
Define synchronizer insertion strategies (2FF, 3FF, handshake, FIFO-based) appropriate to each crossing type, frequency ratio, and data hazard profile; establish metastability MTBF budgets per domain pair.
Drive CDC structural and functional verification using industry-standard tools (Synopsys SpyGlass CDC, Cadence JasperGold CDC, Mentor Questa CDC); own CDC closure criteria and waiver review process.
Author set_clock_groups, case_analysis, and false_path constraints in SDC to accurately model asynchronous relationships; validate that constraint intent matches RTL implementation.
Establish CDC coding guidelines and review checklists for RTL designers; enforce rules via lint and CDC tool flows integrated into the design methodology.
Lead CDC debug and root-cause analysis for functional failures attributable to domain crossings, including post-silicon correlation and errata investigation.
Define CDC sign-off criteria per tape-out milestone; own the CDC waiver database and ensure all open items are resolved or risk-assessed before tapeout.
Timing Constraints - Functional & DFT
Author, own, and maintain comprehensive SDC constraints for functional timing closure across all clock domains, generated clocks, and interface IPs.
Define and manage clock exceptions: false paths, multicycle paths, case analysis, and set_clock_groups for synchronous and asynchronous CDC domains.
Develop DFT-specific clocking constraints for scan shift, scan capture, ATPG, MBIST, and LBIST operating modes.
Architect On-Chip Clock Controller (OCC) strategies for scan clock control and support DFT engineers with test-mode clock mux insertion.
Partner with STA engineers (Synopsys PrimeTime / Cadence Tempus) to drive timing closure and sign-off across all PVT corners.
Integration & Cross-Functional Leadership
Lead clocking architecture reviews with IP owners, SoC architects, physical design leads, and external IP vendors.
Define clocking sign-off criteria for tape-out milestones and own the clocking checklist through tapeout.
Mentor junior and senior engineers on clocking best practices, constraint methodology, and debug techniques.
Represent the clocking team in design reviews, customer technical engagement, and Altera architecture planning sessions.
What Altera Offers
The opportunity to shape clocking architecture for the world’s most advanced programmable logic devices.
A collaborative, engineering-first culture with direct visibility into chip architecture decisions.
Comprehensive benefits: medical, dental, vision, 401(k) with company match, and paid parental leave.
Flexible hybrid work model and dedicated professional development investment.
Access to Altera’s world-class EDA infrastructure, IP libraries, and advanced process node programs.
Salary Range
The pay range below is for Bay Area California only. Actual salary may vary based ona number offactors including job location, job-related knowledge, skills, experiences,trainings, etc. We also offer incentive opportunities that reward employees based on individual and company performance.
$187,000 - $270,700USD
We use artificial intelligence to screen, assess, or select applicants for the position.Applicants must be eligible for any required U.S. export authorizations.
Qualifications:
Minimum Qualifications
Bachelor’s or Master’s degree in Electrical Engineering, Computer Engineering, or a related technical field.
12+ years of industry experience in physical design, SoC/FPGA design, or clocking architecture, with silicon tape-outs at 7nm or below.
Proven ownership of full-chip and subsystem-level clocking architecture on high-complexity SoC or FPGA devices.
Deep expertise across PCIe (Gen4/5/6), DDR5/LPDDR5/HBM, ARM CoreLink/CMN, Ethernet (1G-400G), Configuration interfaces, and SerDes clocking.
Demonstrated experience architecting clocking for ML/AI accelerator silicon: multi-frequency compute/memory/interconnect clock planes, DVFS, and HBM/LPDDR5X integration.
Expert-level CDC architecture ownership: full-chip CDC planning, synchronizer strategy, metastability analysis, and end-to-end CDC sign-off.
Proficiency with CDC verification tools (SpyGlass CDC, JasperGold CDC, Questa CDC) including waiver management and RTL coding guideline enforcement.
Expert-level SDC constraint authoring and validation using Synopsys PrimeTime and/or Cadence Tempus.
Comprehensive DFT clocking experience: scan, ATPG, OCC, MBIST, LBIST, and associated SDC methodology.
Experience with low-power design methodologies (UPF/CPF) and their interaction with clock gating and multi-voltage power domains.
Preferred Qualifications
FPGA or programmable logic background with understanding of fabric clocking resources (PLLs, global/regional clock networks, GCLK/RCLK routing).
Experience with clocking for hard IP subsystems within FPGA SoC devices (e.g., HPS, PCIe hard blocks, memory controllers).
Background in AI/ML FPGA overlay design: knowledge of tensor/matrix engine clocking, dataflow pipeline clock domain partitioning, and AI inference latency optimization through clock architecture.
Experience with formal CDC verification and model checking (VC Formal) for synchronizer correctness proofs.
Familiarity with PLL/DLL characterization, frequency margining, jitter budget analysis, and SSC validation.
Knowledge of IEEE 1500, P1687 (IJTAG), and their clocking implications for embedded DFT instrumentation.
Experience with multi-die/chiplet clocking architectures (UCIe, BoW, AIB) and die-to-die CDC management.
Scripting proficiency in Tcl and/or Python for constraint automation, CDC report parsing, and custom analysis flows.
Familiarity with Intel/Altera FPGA architecture (Stratix, Agilex product families) a significant advantage.