Microarchitect / RTL Design - Memory Subsystem

What You’ll Do

As a Member of the Technical Staff on the RTL Design team at Architect, you’ll own the AI-driven microarchitecture and RTL design of the memory subsystem going into production silicon. You will define, drive, and revise the block-level micro-architecture specification for memory controllers, memory hierarchy management, and memory-side accelerators - ensuring maximum bandwidth utilization, minimal latency, and efficient power delivery for compute-intensive ML workloads.

Core Responsibilities

• Own the memory subsystem RTL end-to-end: from DDR/HBM controller design through code generation, lint, CDC, synthesis, and timing closure using our AI-driven design flow.
• Design and implement memory controllers: including DDR5/LPDDR5X PHY-side controller logic, HBM3/HBM3E pseudo-channel controllers, command scheduling (open-page/close-page policies, bank-level parallelism), refresh management, and ECC/RAS engines.
• Architect the memory hierarchy: including multi-level cache controllers, scratchpad memory managers, coherency protocol engines (where applicable), prefetch engines, and bandwidth partitioning/QoS mechanisms to serve diverse traffic profiles from ML accelerator datapaths.
• Design memory-side accelerators: near-memory compute logic, scatter-gather DMA engines, address translation/remapping units, compression/decompression engines co-located with memory interfaces, and intelligent prefetchers tuned for ML access patterns.
• Work directly with the principal architect to refine microarchitectural specs, resolve implementation trade-offs (bandwidth vs. latency vs. area vs. power), and feed area/timing/power realities back into the architecture and internal AI systems.
• Define and maintain interface specifications: DDR PHY interfaces (DFI), HBM PHY interfaces, on-chip SRAM interfaces, AXI/ACE/CHI for memory-facing fabric ports, and custom interfaces for near-memory accelerator datapaths.
• Build and maintain RTL infrastructure for our in-house AI-driven flow: design automation scripts, regression flows, lint/CDC waivers, and integration collateral for the memory subsystem.
• Close collaboration with DV: Support verification bring-up with memory timing models, protocol-compliant BFMs, SVA assertions for JEDEC protocol compliance, coverage plans targeting worst-case scheduling scenarios, and architectural documentation for verification closure.
• Close collaboration with SW and ML: Support and guide our SW and ML experts to revise and improve our in-house AI flow based on your memory subsystem domain expertise - particularly around workload-driven memory access pattern optimization.
• Support FPGA prototyping on Xilinx for early functional validation of memory controllers, including bring-up with DDR MIG IPs and HBM validation platforms.

Required Qualifications

• Degree: Bachelor’s, Master’s, or PhD in Electrical Engineering, Computer Engineering, or a closely related field.
• Experience: 5+ years (10+ preferred) in RTL design with at least one advanced-node tapeout experience involving memory subsystems (DDR/LPDDR/HBM controllers, cache hierarchies, or memory-intensive SoC subsystems).
• Memory Interface Expertise: Deep familiarity with JEDEC memory standards - DDR5/LPDDR5X command/address protocols, timing parameters, training sequences, and/or HBM2E/HBM3 pseudo-channel architecture, stack addressing, and interleaving schemes.
• Memory Controller Design: Hands-on experience designing or owning memory controller blocks including command schedulers, bank state machines, refresh engines (per-bank, fine-granularity), read/write turnaround optimization, and PHY interface timing (DFI or proprietary).
• Memory Hierarchy Architecture: Experience with multi-level cache design (tag/data arrays, replacement policies, coherence protocols), scratchpad controllers, or unified memory architectures with partitioning and QoS.
• SystemVerilog: Clear, synthesizable, lint-clean RTL with strong design habits - parameterization for multi-standard support (DDR5/HBM3), modularity for channel/pseudo-channel instantiation, and configurability for different capacity/bandwidth targets.
• Block-Level Depth: Hands-on experience with SRAM controllers and arbiters, bank conflict resolution, address hashing/interleaving, ECC encode/decode engines, and high-bandwidth data movement between on-chip and off-chip memory.
• SoC Methodology: Solid grasp of synthesis, timing constraints, clock domain crossings (PHY-to-controller domain, multi-frequency memory interfaces), reset strategies, AMBA protocols (AXI, ACE, CHI), and power management for memory subsystems.
• Python: Strong skills for design automation, performance modeling, regression infrastructure, and tooling.
• PPA Ownership: Experience taking a memory controller or cache subsystem from RTL through synthesis and working with PD teams on timing/area/power closure - particularly for high-frequency controller logic and wide data buses.

Bonus Qualifications

• Experience with HBM integration: interposer-level considerations, PHY calibration, thermal management impacts on refresh.
• Familiarity with CXL memory pooling, Type 3 device controllers, or disaggregated memory architectures.
• Near-memory or processing-in-memory (PIM) design experience.
• Low-power design techniques: DVFS-aware memory scheduling, partial-array self-refresh, clock gating of idle channels, power gating of unused banks.
• FPGA prototyping experience (Xilinx Vivado/Vitis) with DDR MIG or HBM subsystem IP integration.
• SVA assertions for JEDEC protocol compliance (command sequencing, timing parameter checking, training state machines).
• Prior IP building and delivery experience for DDR/LPDDR controllers, HBM controllers, or cache subsystem IPs.
• Performance modeling: experience building or using cycle-accurate memory system simulators (e.g., DRAMSim, Ramulator) to validate microarchitectural decisions.
• Domain-specific research contributions: publications or patents in memory systems, memory scheduling algorithms, or memory-centric compute architectures for ML workloads.

Why Architect

You’ll join a founding team building the future of chip design at the intersection of AI and silicon. Your memory subsystem expertise will directly shape production ASICs - enabling the bandwidth and efficiency that ML workloads demand - and influence how AI transforms hardware development from spec to tapeout.