AI servers and high-speed network equipment all require high-density, high-power BGA-packaged components like GPUs, FPGAs, ASICs, and CPUs. Their mainboards are high-speed digital HDI PCBs.
PCBONLINE specializes in one-stop PCB manufacturing and assembly for HDI high-speed PCBs for AI servers and high-speed network equipment like switches, routers, and data center interface cards. Our PCBs for AI servers and high-speed networks have different layers and design focuses, but they both transmit high-speed digital signals at a Gbps rate.
High-speed Digital PCB for AI Servers and High-Speed Network Equipment
First, what is a high-speed digital circuit? High-speed digital signals are >500MHz or data rates >1Gbps. Especially, the GPU PCB with 24+ layers is the most typical. Its circuit design must consider signal integrity, power integrity, and electromagnetic compatibility (EMC), involving extremely high data transmission rates and synchronization requirements.
AI servers and high-speed network equipment are typical high-speed digital devices that transmit high-speed differential signals, such as PCIe, DDR5, SerDes, PAM4, etc. Their PCBs require high-density, large-format BGA-packaged chips, such as GPUs, FPGAs, and ASICs, and simultaneously satisfy the requirements for high-density interconnect and high-speed signal integrity.
Consequently, the PCBs of AI servers and high-speed network equipment, including their mainboards, are HDI high-speed digital PCBs.
The mainboards for AI servers, switches, and GPU accelerator cards are all high-frequency/high-speed, combined with high-density BGA layouts. The features of high-speed digital PCB design for AI servers and high-speed network equipment are listed below.
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Design dimension
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Explanation
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Functional component
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GPUs, FPGAs, CPUs, and ASICs are all high-speed digital processing components.
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Signal type
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High-speed differential signals, such as CIe, SerDes, Ethernet, and DDR buses, are utilized.
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Structural requirement
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Fine BGA pitch ≤ 0.5mm necessitates the use of HDI structures like blind, buried, and laser micro vias.
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Electrical requirement
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High data rates mandate strict control over impedance, crosstalk, reflection, and timing skew.
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Material Requirement
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Low-loss FR4 materials, such as MEGTRON 6 and Isola 370HR, are adopted to ensure signal integrity.
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How about the differences between PCBs of AI servers and high-speed network equipment? They require different critical components and transfer digital signals at different rates.
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Feature
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High-speed digital PCB for AI servers
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High-speed digital PCB for high-speed network
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Critical components
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GPU, CPU, FPGA, HBM, DDR5, PCIe controllers
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ASIC, FPGA, PHY, MAC, switch chips
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Digital signal rate
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PCIe Gen5/6 (32-64Gbps, DDR5(6400 MT/s)
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25G/56G/112G PAM4, SerDes Links
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Transmission type
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High-speed differential signals, SerDes, memory bus
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High-speed differential signals, Ethernet Links
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Design focus
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Signal integrity, impedance control, clock synchronization
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Eye diagram, jitter, reflection, crosstalk, loss control
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HDI layer
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12-24 or more (GPU PCBs with 24+layers are typical)
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8-20 or more
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Why is the high-speed digital PCB for AI servers and high-speed networks HDI?
HDI (High Density Interconnect) and high-speed digital are two separate but related dimensions for a PCB.
HDI focuses on routing density, involving micro-blind vias, buried vias, fine line width, and stackup design.
High-speed digital focuses on signal rate and integrity, involving impedance matching and crosstalk control.
High-speed digital PCBs often adopt an HDI structure to support high-density BGA packaging, especially in products for AI servers, data centers, and high-speed network equipment. While HDI is not strictly a prerequisite for high speed, it achieves high-density, high-speed interconnection.
High-speed/high-frequency products in high-end data rates, including DDR5, PCIe 5/6, and SerDes 56G/112G interfaces, use the HDI technology. This is because the pitch of high-speed chip packages (BGA pitch below 0.5mm) is too dense for routing with traditional through-holes. So the high-speed digital PCBs for AI servers and high-speed networks use blind/buried/micro via stack-ups.
High-speed digital PCB material: FR4 or. PTFE?
From the above, we learn that the PCBs for AI servers and high-speed network equipment have to transmit high-speed digital signals and use the HDI technology simultaneously.
High-speed/high-frequency PCBs can adopt low-Dk/Df FR4 PCB materials or PTFE/Rogers materials.
While HDI PCBs are usually FR4 PCBs or rigid-flex PCBs, in the layer structures of FR4 + PI + FR4. As an advanced PCB manufacturer, we rarely use PTFE or Rogers materials.
So the answer to PCB material selection for AI servers and high-speed network equipment is FR4.
Specifically, the material for high-speed digital PCBs is modified FR4, also called Low-Dk/Df FR4.
MEGTRON 6, Isola 370HR, Nanya NY6300G, Shengyi Synamic 6N, and 6GN, are available PCB laminates for PCBONLINE to fabricate the high-speed digital PCBs for AI servers, routers, data center interface cards, etc.
We do not select standard FR4 and PTFE materials, but modified FR4, and sometimes we can also select PTFE+FR4 materials for a hybrid stackup for high-speed digital PCBs.
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PCB material
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Application
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Characteristic
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Used in high-speed digital or not
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Standard FR4
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Standard multilayer PCBs, low-speed logic PCBs
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Unstable Dk (≈4.3-4.7), high loss (Df ≈0.02)
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Suitable for medium speeds (≤5Gbps), low cost
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Modified FR4 like MEGTRON 6, Isola 370HR, IT-180A, Nanya NY6300G, Shengyi Synamic 6N
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High-speed digital PCBs (AI servers, switch mainboards)
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Low-loss FR4-class material, Dk ≈3.7, Df ≈0.005-0.009
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The mainstream choice. It offers high cost-performance
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PTFE (Polytetrafluoroethylene), like Rogers 3003/4350B, Taizhou Wangling F4B
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Microwave/RF circuits, 5G antennas
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Extremely low loss, stable Dk
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Generally not used for purely HDI high-speed digital PCBs
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Hybrid stackup
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Specific high-speed channels
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PTFE for critical high-speed signal layers, FR4 for other layers
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High-end communication equipment
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Examples of High-speed Digital PCB: PCBONLINE's AI Server and High-Speed Equipment PCB
This image shows an AI server PCB manufactured by PCBONLINE. It features:
- GPU BGA pad zone: The dense white pad array is for a high-performance GPU package.
- HDI interconnections: Buried and blind vias connect inner layers, supporting high-speed GPU-to-memory routing.
- High reliability: Fabricated under IPC-A-610 Class 3 industrial grade standards, ensuring long-term operation in data centers.
PCBONLINE not only produces the high-speed digital PCB for AI servers but also provides its full PCBA services, including SMT and THT assembly, functional testing, IC programming, and burn-in testing.
Besides AI servers, PCBONLINE also fabricates and assembles high-speed digital PCBs for high-speed network equipment, and the following is a PCBA example made by us.
Partner with PCBONLINE for Turnkey High-speed Digital PCBs for AI Servers
If you are designing PCBs or mainboards for AI servers and any high-speed network equipment, work with PCBONLINE for a turnkey high-speed digital PCB. We provide AI server PCB manufacturing services that cover GPU PCB manufacturing, assembly, testing, and reliability assurance.
Founded in 2005, PBONLINE has two large advanced PCB manufacturing bases and one PCB assembly factory.
AI server PCB fabrication with HDI via-in-pad copper filling for GPU designs with 24+ layers.
We provide one-stop high-speed digital PCB manufacturing, including component sourcing, PCB fabrication, assembly, testing, and system integration.
SMT assembly with fine-pitch BGA placement accuracy and custom reflow profiles for warpage-free soldering.
100% X-Ray inspection, functional testing, and burn-in testing for guaranteed reliability.
We have rich experience in impedance control, oven temperature control, and assembly fixture designs.
Supporting IC programming in the Cloud way, manipulated by you, and protecting your intellectual property.
High-quality PCBA manufacturing certified with ISO 9001:2015, ISO 14001:2015, IATF 16949:2016, RoHS, REACH, UL, and IPC-A-610 Class 2/3.
At PCBONLINE, we can help our clients reduce costs while achieving the highest levels of performance and reliability. If you feel interested in high-speed digital PCBs for AI servers and high-speed network equipment from PCBONLINE, send your inquiry by email to info@pcbonline.com.
Conclusion
High-speed digital PCBs for AI servers and high-speed equipment are typically 24+-layer HDI PCBs powering GPUs for deep learning and high-performance computing. As the global demand for AI computing grows, China supplies over 70% of AI server PCBs, with PCBONLINE standing out as a reliable turnkey AI server PCB manufacturer. If you are looking for a trusted partner for high-speed digital PCBs, contact PCBONLINE for turnkey OEM manufacturing.
PCB assembly at PCBONLINE.pdf
