Mouser - White Papers

Mouser Electronics White Paper Liquid cooling benefits from liquids' higher thermal conductivity and heat capacity compared with air. Liquids transport energy more efficiently within a confined space. Further, capturing heat at the device interface prevents it from accumulating within the chassis. Taking advantage of liquid cooling's benefits calls for new solutions to critical design considerations. Liquid cooling methods require different connectors than air cooling. Tubing and couplings must maintain sealing integrity under pressure, and connectors must function reliably within compact spaces already populated by high-speed signal paths and power distribution hardware. Amphenol LTW SnapQD liquid cooling connectors address the needs of cold plate systems. Their compact design supports dense assemblies, while quick-disconnect functionality simplifies maintenance and component replacement. Also, their secure sealing mechanisms help maintain leak-free operation under sustained load. As liquid distribution extends beyond individual cold plates, fluid routing becomes another important design consideration. Engineers must route fluid lines through tight spaces without blocking nearby components. To help achieve this, connector orientation can simplify the overall layout. Amphenol Industrial UQD and UQDB liquid cooling connectors offer a range of sizes and geometries, including right-angle formats suited to confined rack environments. With durable materials and secure coupling mechanisms, these connectors support continuous operation in high-density installations. Most facilities adopt a mixed cooling strategy. While air cooling works well for low-power components and for maintaining stable room conditions, liquid cooling is used where the heat is most concentrated, such as in GPUs. This approach makes it easier to gradually scale as compute density increases. Power Density and Electrical Distribution Thermal management is directly linked to power architecture. High- performance accelerators routinely consume several hundred watts per device, and a rack populated with accelerators, storage devices, and networking hardware can approach several hundred kilowatts. Industry roadmaps and hyperscale deployments now show rack power densities approaching 1MW for AI-focused installations. 5 Electricity enters the facility at high voltage. It then passes through uninterruptible power supplies and distribution units before reaching individual servers. Each interface along that path contributes resistance. According to P = I²R, energy loss increases with the square of current. At elevated current levels, small increases in resistance translate into greater energy loss and measurable heat, making connector choice all the more important. Connector design affects both power efficiency and thermal load. In today's data centers, low contact resistance must be maintained over many mating cycles. Compact footprints are necessary in 1U and 2U power shelves where space remains limited. Amphenol Positronic OCP ORV3 universal AC input connectors conform to Open Compute Project (OCP) Open Rack V3 (ORV3) specifications for components used in rack system deployments. These connectors' slim profile makes them suitable for rack-mounted power systems. In addition, high- conductivity alloys reduce terminal resistance, while recessed contacts enhance safety in high-current environments. Converging Power and High-Speed Interfaces In all data center installations, the pressure to manage board space grows as system density increases. Combining power delivery and high-speed signaling into shared connector interfaces reduces routing complexity and preserves printed circuit board (PCB) area. But combining power and signals in the same connector housing poses risks for signal integrity. PCIe Gen 6 and related interconnect technologies employ advanced modulation schemes, such as pulse amplitude modulation with four levels (PAM4), to increase throughput without doubling channel frequency. These techniques demand careful control of impedance, insertion loss, and crosstalk. Amphenol FCI Hyper Cool Edge connectors support hot-pluggable connectivity for accelerator, Compute Express Link (CXL), and network interface modules while accommodating modern high- speed signaling. They can deliver up to 200W of power, and the dedicated two-pin power receptacle can supply an additional 400W. Integrating power and data within a shared connector supports higher board-level density and simplifies system integration. Conclusion AI-driven workloads pack more computing power into smaller physical footprints. As rack density increases, heat generation rises, and efficiency becomes harder to maintain, further intertwining thermal and power limits. Decisions in one area directly affect the others. While standards provide structure, performance depends on implementation. Distributed temperature sensing strengthens HVAC feedback, but what remains essential is the system response to

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