Client Background
Our client, a U.S.-based enterprise storage company located in California, specializes in custom NVMe SSD modules for cloud servers and edge computing. They needed a trusted partner to handle the PCB design for a high-speed U.2 NVMe storage module aimed at Tier 1 data centers.
Client’s Challenge
The client faced multiple technical and production-related hurdles:
- PCIe Gen4/Gen5 compatibility for backward and forward support.
- 4-channel NAND flash configuration with a high-speed interface.
- Compact 2.5-inch form factor with tight mechanical constraints.
- Strict requirements for signal integrity, power stability, and thermal performance under continuous read/write cycles.
- Desire for fast design turnaround and DFM-ready output for contract manufacturers in Asia.
Our Solution & Technical Implementation
1. Stack-up & High-Speed Routing Strategy
We selected a 10-layer stack-up with low-loss materials (Panasonic Megtron 6 equivalent), enabling:
- Controlled impedance routing for PCIe x4 lanes at 16 GT/s.
- Optimized layer assignment for power and ground to reduce EMI and crosstalk.
- Tight trace length matching (<5mil) for differential pairs, especially between controller and NAND flash chips.
2. Signal Integrity & Power Integrity Simulation
We performed full SI/PI simulations using HyperLynx and Ansys tools:
- Ensured eye diagram margins passed PCIe compliance at Gen4 speeds.
- Simulated power delivery network (PDN) to maintain voltage ripple <20mV during peak I/O.
- Adjusted decoupling capacitor placement and values based on real-time analysis.
3. Thermal Design
We applied thermal modeling to identify hotspots:
- Integrated copper heatsink pads directly under the NAND packages.
- Added multiple thermal vias and optimized airflow pathways.
- Reserved space for a passive heatsink attached during final assembly.
4. Firmware Collaboration & Pinout Mapping
Worked closely with the client’s firmware team to:
- Finalize pin assignments for flash controller and firmware debug ports (JTAG/UART).
- Label and document all test points, bootstraps, and power sequence nets for firmware flashing and testing.
5. Design for Manufacturability (DFM)
Delivered production-ready Gerber, ODB++, and assembly files:
- Clear solder mask and paste layers for automated assembly.
- Fiducial placements, tooling holes, and pick-and-place coordinate files.
- Added silkscreen instructions for AOI and ICT alignment during testing.
6. Prototype Testing & Revision
Prototypes were produced through our recommended EMS partner:
- First-pass success on functional and stress tests at 70°C operating temperature.
- Helped client validate the endurance and power-loss protection functions.
- Minor revision (V1.1) implemented to optimize EMI shielding footprint near the crystal oscillator.
Client Feedback
“Your team understood our signal and power constraints better than any outside design partner we’ve worked with. We hit PCIe Gen4 specs on the first prototype, and your help on thermal and DFM saved us time during pilot production. Looking forward to the next series.”
— Hardware Systems Manager, USA
Result
The project went from schematic planning to fully tested production boards in just 6 weeks. The final module is now used in edge storage servers and industrial rack systems in data centers across North America and Europe.
