DPU Accelerator Card PCB Applications and Manufacturing Challenges

AI computing, cloud data centers, and high-performance computing platforms handle large volumes of network, storage, and security-related data traffic. DPUs (Data Processing Units) can handle tasks such as network transmission, storage access, security, and infrastructure management, offloading some infrastructure processing workloads from host CPUs. As DPU network bandwidth and host interface speeds increase, high-speed interconnections on accelerator cards place greater demands on PCB signal transmission performance, manufacturing precision, and long-term reliability.

DPU accelerator cards typically integrate DPU chips, high-speed network interfaces, memory, power circuits, and other functional components, and connect to server systems through high-speed interfaces such as PCIe. Different products vary in network speeds, interface configurations, board architectures, and functional designs. PCB materials, stack-up structures, and interlayer interconnection methods must therefore be determined according to specific product specifications.

HoYoGo is a professional DPU accelerator card PCB manufacturer with capabilities in high-reliability, high-precision, multilayer, and high-speed PCB manufacturing. DPU accelerator cards place demanding requirements on high-speed signal transmission, dense interconnections, and long-term operation. This article outlines key PCB manufacturing considerations, including manufacturing precision, low-loss materials, multilayer interconnection, back drilling, and reliability.

PCB Manufacturing Precision for High-Speed Interfaces

DPU accelerator cards involve high-speed data transmission between DPU chips, network interfaces, memory, and host interfaces. For controlled-impedance traces, factors such as trace width, trace spacing, copper thickness, dielectric thickness, and material properties can affect actual impedance.

PCB manufacturing requires careful control of trace dimensions, copper thickness, dielectric thickness, etching uniformity, and other key parameters according to customer-specified stack-up structures, impedance targets, and technical requirements. Controlled-impedance traces must also be tested under specified conditions to verify that their actual impedance falls within the required tolerance range.

Low-Loss Materials and High-Speed Signal Transmission

High-speed signals traveling through a PCB are subject to both dielectric and conductor losses. For some DPU accelerator card PCBs, factors such as dielectric constant (Dk), dissipation factor (Df), copper foil surface roughness, and trace geometry can affect transmission loss along high-speed traces.

Some DPU accelerator card PCBs may use low-loss materials depending on trace geometry, transmission distance, and product performance requirements. Different materials vary in resin systems, dimensional stability, and processing characteristics. Manufacturing conditions for lamination, drilling, and circuit fabrication must therefore be determined according to material properties. Dielectric thickness after lamination and the consistency of related structural parameters also require careful control.

Multilayer PCBs and High-Density Interconnections

DPU accelerator cards must support high-speed signal interconnections and power connections among multiple functional modules within limited board space. Multilayer PCBs provide the foundation for configuring signal, power, and ground layers.

For PCBs with high routing density and complex interlayer interconnections, processes such as layer-to-layer registration, lamination, drilling, and hole metallization require consistent control. Some high-density DPU accelerator card PCBs may also use HDI structures with microvias and other interlayer interconnection features, depending on design requirements. For these PCBs, particular attention should be paid to layer-to-layer registration, hole position accuracy, laser drilling quality, and hole metallization.

High-Speed Vias and Back Drilling

When high-speed signals transition between layers on DPU accelerator cards, vias are typically used to provide electrical connections. For some high-speed traces, unused portions of vias, known as via stubs, may cause reflections and affect signal transmission performance.

Depending on the specific stack-up and high-speed trace design, some DPU accelerator card PCBs use back drilling to remove copper plating from unused sections of plated through-hole vias, thereby reducing via stub length. During manufacturing, back-drill depth, positional accuracy, and remaining stub length must be controlled according to customer drawings, the PCB stack-up, and target layer positions.

PCB Reliability Under Thermal Load

DPU chips, high-speed network interfaces, and power components generate heat during continuous operation. Overall thermal management of the accelerator card depends primarily on system thermal design, but the thermomechanical properties of PCB materials, interlayer bonding, and via interconnection quality can also affect long-term reliability.

For PCBs operating at elevated temperatures over extended periods or exposed to temperature cycling, materials must be selected according to product operating conditions and reliability requirements. Lamination quality, interlayer bonding, and hole-wall copper plating quality also require careful control to reduce the risk of delamination and barrel cracking during long-term operation.

Manufacturing Consistency in Volume Production

Once DPU accelerator card PCBs enter volume production, maintaining consistency across production batches becomes an important consideration. Variations in material properties, dielectric thickness, trace dimensions, copper thickness, and via structures can affect the impedance, dimensions, and electrical performance of finished PCBs.

From raw material management and inner- and outer-layer circuit fabrication to lamination, drilling, electroless copper deposition, electroplating, and final electrical testing, each critical manufacturing process requires consistent control to ensure that PCBs produced in volume meet the specified technical requirements.

Impact of DPU Development on High-Speed PCB Manufacturing

DPUs are evolving toward higher network bandwidth, greater data processing capabilities, and faster host interconnections. As interface speeds increase, PCB manufacturing faces more stringent requirements for low-loss materials, precision circuit fabrication, impedance control, multilayer interconnections, and complex via fabrication.

Different DPU accelerator cards vary in chips, network interfaces, board architectures, and stack-up designs. PCB materials and manufacturing processes must therefore be determined according to specific product specifications and customer technical requirements.

HoYoGo is a professional DPU accelerator card PCB manufacturer with capabilities in high-reliability, high-precision, multilayer, and high-speed PCB manufacturing. To meet the requirements of DPU accelerator cards for high-speed signal transmission, complex interconnections, and manufacturing consistency, we provide customized PCB manufacturing services based on customer product specifications and technical requirements. Production and quality control are carried out according to applicable IPC standards and customer technical specifications, providing reliable PCB manufacturing support for DPU accelerator cards and related data center hardware.