Overview
This custom carrier board is designed to interface with Xilinx Ultrascale+ system-on-module (SoM) platforms, providing a complete development environment for high-speed digital designs. The board features multiple high-speed interfaces, DDR4 memory, and flexible I/O options for prototyping and evaluation.
The design focuses on signal integrity for multi-gigabit transceivers, proper power sequencing for the FPGA fabric, and thermal management for sustained high-performance operation.
Key Features
- Xilinx Ultrascale+ SoM connector (high-density Samtec)
- DDR4 SODIMM socket supporting up to 16GB
- 4x SFP+ cages for 10Gbps optical/copper connectivity
- PCIe Gen3 x8 edge connector
- USB 3.0 Type-C with USB-PD support
- Gigabit Ethernet with IEEE 1588 PTP support
- JTAG and UART debug interfaces
- Onboard power management with sequencing
- FMC HPC connector for expansion
Technical Specifications
| Board Dimensions | 170mm x 170mm (Mini-ITX form factor) |
|---|---|
| Layer Count | 12 layers (6 signal, 4 plane, 2 mixed) |
| Stack-up | Megtron 6 / FR4 hybrid for controlled impedance |
| Min Trace/Space | 3.5mil / 3.5mil |
| Via Technology | Blind/buried vias, back-drilled stubs |
| Power Input | 12V DC barrel jack or USB-C PD (up to 100W) |
| Power Rails | 0.85V, 1.0V, 1.2V, 1.8V, 2.5V, 3.3V, 5.0V |
Design Challenges
High-Speed Signal Integrity
The GTY transceivers operate at up to 16Gbps, requiring careful attention to trace geometry, reference planes, and via transitions. I used Altium's PDN analyzer and 3D field solver to optimize the channel characteristics.
Power Distribution
With over 50A peak current draw, the PDN required extensive decoupling and low-impedance power planes. The FPGA core voltage uses a 6-phase buck converter with adaptive voltage positioning.
Thermal Management
Active cooling is provided through a custom heatsink mounting system. Thermal vias under power components and proper copper pours help distribute heat across the board.
Gallery
