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Molex XPO connector, twinax cables and co-packaged copper solution.

XPO Connector Assemblies for eXtra-Dense Pluggable Optics

XPO Connector Assemblies, the next-generation pluggable optical solution for large AI fabrics and hyperscale cloud and data centers, are optimized for extreme bandwidth density, superior reliability and power efficiency. The ultra-high-density XPO interface delivers four times the front-panel density of OSFP connections, enabling up to 204.8Tbps of switching capacity within a single open-rack unit. BiPass flyover architecture terminates low-loss twinax cable directly to the XPO connector and co-packaged copper (CPC) solution, ensuring exceptional signal integrity and scalability to support data rates of 224G and beyond.

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Features and Benefits

The growth of AI has fundamentally changed data center architecture requirements, presenting new challenges related to extreme bandwidth, high connection density, thermal management, power efficiency and scalability. System architects for high-bandwidth systems now face the “radix wall”—the physical limitations of front-panel real estate. With speeds accelerating to 224G and beyond, demands become more stringent for improved signal integrity, power efficiency and thermal performance.

The solution for conquering the radix wall problem is ultra-high-density, high-speed connectors capable of exceptional signal integrity (SI) and reliable performance at 224G+ speeds. These connections must provide dependable, low-loss operation and enable scalable, field-serviceable architectures that support next-generation bandwidth capabilities.

XPO Connector Assemblies from Molex use the ultra-high-density, pluggable XPO interface to meet this need, delivering four times the front-panel density of OSFP connectors within the same rack-unit space. With 128 differential pairs and 64 channels of 224G PAM-4 connectivity per XPO Connector Assembly, the XPO design minimizes space requirements and accelerates time to capacity. BiPass flyover architecture, using direct termination to low-loss twinax cables and co-packaged copper (CPC), helps minimize the need for long PCB traces, reducing loss and delivering predictable SI margins. High-voltage, passthrough power architecture and support for liquid cooling enable XPO modules to run at higher power safely, thereby helping avoid massive chassis redesigns. The pluggable XPO connector was developed by Molex as part of the multi-vendor service agreement (MSA), improving scalability and minimizing supply chain risk by offering hyperscale data centers an interoperable ecosystem of high-performance connectivity solutions.

XPO Connector Assembly Solution for Reduced Insertion Loss

The XPO system delivers reliable 224G PAM-4 connectivity, with a roadmap toward 448G speeds, by connecting low-loss Molex BiPass twinax cables directly to the XPO connector-and-cage assembly and to the Impress Co-Packaged Copper (CPC) Solution. This flyover architecture bypasses long PCB traces for enhanced signal integrity and performance by lowering jitter and bit error rates (BER), reducing forward error connection (FEC) burden and smoothing the insertion loss (IL) slope.

Molex XPO connector with cage connected to Molex Impress Co-Packaged Copper solution using Molex BiPass twinax cables.

Integrating 128 Differential Pairs per XPO Connector for Maximum Density

High-density XPO connectors provide twice the usable I/O connectivity per open rack unit (1OU) by delivering 128 differential pairs and 64 high-speed channels in a compact form factor. Each XPO Connector Assembly delivers 12.8Tbps, enabling up to 204.8Tbps per 1OU in support of higher-radix switches, fewer racks, faster time to capacity and lower facility cost per bit for hyperscale AI fabrics.

Molex XPO connector with 128 differential pairs.

Direct Termination into the XPO Connector Assembly for System Simplification

By using low-loss twinax cables terminated directly to the XPO connector and the Impress Co-Packaged Copper (CPC) solution, XPO Connector Assemblies extend the practical reach of high-speed electrical connections and require fewer re-timers. The low latency and low IL help reduce the need for complex physical-layer turning, simplify board layouts and minimize performance trade-offs for high-density architectures.

Molex XPO connector assembly directly terminated to twinax cables.

Reduces footprints for high-bandwidth AI applications
The ultra-high-density XPO interface uses 64-lane pluggable modules that deliver massive bandwidth in a compact footprint. The design supports up to 12.8Tbps per module and up to 204.8Tbps per 1OU, enabling customers to double front-panel I/O density or increase compute power per rack without expanding real estate.

Enables high speeds by supporting superior signal integrity
Using BiPass flyover architecture that integrates directly terminated twinax cable and Impress Co-Packaged Copper (CPC) Solutions, the Molex XPO system helps make reliable 224G—and future 448G—links achievable by minimizing IL and parasitics, lowering BER and FEC burden.

Minimizes the risk of substrate damage
The reworkable compression socket and mechanical ejector/pull-tab design ease insertion and removal while protecting the substrate during assembly and servicing. They also improve field reworkability, increase the mean time between failures (MTBF) of front-facing modules, and reduce maintenance costs.

Reduces connector size requirements
The high-voltage, high-power contact and passthrough construction supports 40 to 60V (commonly 48 to 50V) and up to 480W in a compact form factor, simplifying rack power architecture without requiring major motherboard redesigns.

Shortens validation cycles and accelerates deployments
Interoperability and alignment with the XPO MSA, host footprints, mechanical tolerances and telemetry/power management standards reduce supply chain risks, simplify system integration, and streamline engineering work for development and testing.

Documents and Resources

Applications by Industry

This is not a definitive list of applications for this product. It represents some of the more common uses.

Frequently Asked Questions

What is the XPO (eXtra-dense Pluggable Optics) system?

The XPO system is a next-generation pluggable-optics architecture designed for hyperscale AI networks. XPO interfaces deliver 12.8Tbps per module by using 64 high-speed electrical lanes, enabling 204.8Tbps per 1OU with four times the front-panel density of OSFP connectors.

What data rates and lane configurations are supported by the XPO interface?

XPO connectors are built for 64 high-speed lanes per module (documented at 224Gbps PAM-4 per lane with a roadmap to data rates as high as 448Gbps), delivering up to 12.8Tbps per module and enabling up to 204.8Tbps within a single 1OU switch configuration.

How does the XPO connector improve signal integrity (SI)?

Molex BiPass flyover architecture minimizes the use of lossy PCB traces by terminating twinax cable directly into the XPO connector and onto the substrate via the Impress CPC connector. This reduces IL and parasitics, minimizes BER and FEC burdens, and provides a smoother IL slope for predictable SI margins.

What power architecture does the XPO connector support?

The Molex XPO connector is designed for a high-voltage rack bus (40 to 60V nominal, commonly 48 to 50V) to enable per-module power budgets from 400 to 480W per module. On-module 48-to-3.3V voltage regulators simplify motherboard layouts and reduce power connector size.

How does Molex address serviceability and rework risk?

The Impress CPC compression socket protects the substrate by providing a non-surface-mount (SMT) compression interface, enabling reworkable connections and reducing the risk of damage to the expensive ASIC substrate during assembly or field service.

What mechanical density and form factor does the XPO interface provide?

The XPO interface is a wider, higher-density form factor than the OSFP design, with a footprint about 2.7 times wider (and eight times higher bandwidth per module) compared with OSFP connectors. Typical XPO interface dimensions are 60.8mm wide, 111.8mm long and 21.3mm high, supporting two rows of modules per 1OU, with each module containing a single connector terminating 64 channels (128 differential pairs). This enables customers to double front-panel lane density.

Do Molex XPO parts interoperate with those from other vendors?

The XPO interface is an MSA-driven form factor. Molex participates in the MSA and provides integration resources (CAD, footprints, mechanical tolerances and recommended host designs) to support multivendor interoperability. Users should validate interoperability with their ASIC/optics partner matrix.

What telemetry, management and control interfaces do XPO connectors support?

The Molex XPO platform supports standard module management interfaces (I2C/I3C, PMBus/I2C telemetry) and can convey temperatures, voltages, per-lane counters and fault/status via register maps. Molex provides management-interface guidance and engineering support for integration.