Molex’s In-Depth Report on Thermal Management Solutions for I/O Modules addresses the limitations of legacy thermal characterization and management approaches.   It explores innovative cooling solutions for servers and optical modules to support the growing demands of 112G and 224G connectivity.

“As demand for faster and more efficient data processing and storage rises rapidly, so does the heat generated by high-performance servers and systems required to scale generative AI applications and facilitate the transition from 112 Gbps PAM-4 to 224 Gbps PAM-4,” said Doug Busch, VP & GM, Enabling Solutions Group at Molex.   “The integration of optical connectivity and modules, combined with new cooling technologies, will optimize airflow and thermal management in next-gen data centers.   Molex is driving innovations in thermal management across both copper and optical platforms, as well as within our power management products, to help customers improve cooling capabilities and enhance energy efficiency in these environments.”

Shift to 224 Gbps PAM-4 Highlights Innovative Liquid Cooling

The transition to 224 Gbps PAM-4 interconnects between servers and network infrastructure represents a doubling of the per-lane data rate.   Power consumption is also surging, with optical modules reaching as high as 40W over long-range coherent links—up from 12W just a few years ago—resulting in nearly fourfold increases in power density.

In this informative report, Molex examines the latest air cooling techniques alongside the integration of innovative liquid cooling solutions within existing form factors to meet the increased power and thermal demands of I/O modules.

The report covers direct-to-chip liquid cooling, immersion cooling, and the role of passive components in enhancing active cooling.   It also identifies cooling methods that are most effective for managing power demands in chips and I/O modules that scale to high levels.

To tackle persistent challenges in cooling pluggable I/O modules, Molex introduces a liquid cooling solution called the integrated floating pedestal.   Each pedestal that contacts the module is spring-loaded and moves independently, allowing the implementation of a single cold plate across different 1xN and 2xN single-row and stacked cage configurations.   For instance, this solution for a 1×6 QSFP-DD module utilizes six independently moving pedestals, which compensate for varying port stack heights while ensuring seamless thermal contact.   This design minimizes thermal resistance and maximizes heat transfer efficiency by allowing heat to flow directly from the module to the pedestal.

The report also outlines the costs and risks associated with immersion cooling, which provides highly effective thermal management exceeding approximately 50kW per rack but necessitates a complete overhaul of a data center’s architecture.

Molex Drop Down Heat Sink (DDHS) Technology

Beyond liquid cooling, Molex’s report details advanced approaches to module design and thermal characterization that promise to enhance the performance of high-speed network interconnects.   New solutions can be integrated into servers and switches for greater heat sinking without compromising reliability.   The report describes an innovative Molex Drop Down Heat Sink (DDHS) solution that maximizes the heat transfer capability of traditional riding heat sinks while minimizing metal-to-metal contact, which can cause wear and tear on components.

With the DDHS, Molex replaces current riding heat sinks with a solution that eliminates direct contact between the optical module and thermal interface material (TIM), resulting in a simpler and more durable installation without friction or piercing.   Consequently, Molex’s DDHS allows successful TIM implementation for over 100 insertion cycles.   This reliable heat management solution fits within standard module and rackmount form factors while effectively cooling higher power modules and improving overall power efficiency.

Future of Optical Module Cooling

As an active participant in the Open Compute Project (OCP) and its Cooling Environments project, Molex is collaborating with industry leaders to develop next-gen cooling technologies that meet the evolving thermal management needs of today’s most demanding data center environments.