400G QSFP-DD Direct Attach Copper Cable (DAC) – PAM4

• Supports aggregate data rates up to 400Gbps using PAM4 signaling
• QSFP-DD form factor for high-density 400G connectivity
• Compatible with IEEE 802.3bj and IEEE 802.3cd
• Optimized cable construction for reduced insertion loss and crosstalk
• Pull-to-release slide latch design for easy installation and removal
• Available with 28AWG and 30AWG cable options
• Straight-through and breakout assembly configurations available
• Customized cable braid termination helps reduce EMI radiation
• Customizable EEPROM mapping for cable identification and system compatibility
• Designed for short-distance, high-bandwidth interconnects
• RoHS compliant

• 400G data center switch-to-switch connections
• 400G switch-to-server interconnects
• Top-of-rack (ToR) networking
• High-performance computing (HPC) networks
• AI and GPU cluster interconnects
• Data center spine-and-leaf architectures
• High-density server and network equipment
• Short-distance rack and equipment interconnections

OEM and ODM customization is available for the 400G QSFP-DD DAC Series to meet specific system and deployment requirements. Custom options can include cable length, cable gauge, labeling, connector configuration, EEPROM mapping, and other cable assembly specifications.

For volume deployments, customized cable construction and braid termination can also be provided to address specific cable-management, mechanical, and EMI requirements. EEPROM programming can be tailored to customer-defined cable identification and equipment compatibility requirements.

What does PAM4 mean in a 400G QSFP-DD DAC?

PAM4, or four-level pulse amplitude modulation, enables two bits of information to be transmitted per signal symbol. This allows the cable to achieve higher aggregate bandwidth while maintaining a practical lane count and electrical interface for 400G networking.

What is the advantage of using a 400G DAC instead of optical connectivity?

A DAC integrates the electrical connectivity into a single cable assembly, eliminating the need for separate optical transceiver modules. For short-distance connections, this can provide a simpler and more economical solution with lower power consumption and fewer components.

What is the difference between straight and breakout configurations?

A straight configuration provides a direct QSFP-DD-to-QSFP-DD connection, while a breakout configuration divides the high-speed connection into multiple lower-speed connections. The appropriate configuration depends on the port architecture and supported breakout modes of the connected equipment.

Why are 28AWG and 30AWG options available?

Different cable gauges provide different combinations of flexibility, cable diameter, thermal characteristics, and mechanical properties. A thinner 30AWG cable can be advantageous in high-density installations where cable management and airflow are important, while 28AWG can provide a more robust cable construction.

How should the maximum cable length be determined?

The suitable cable length depends on the electrical performance requirements of the specific application and the system configuration. Shorter DAC assemblies are generally preferred for high-density rack environments because they reduce cable bulk and help maintain efficient airflow. Custom lengths can be supplied according to deployment requirements.

Can the EEPROM be customized for specific networking equipment?

Yes. The EEPROM mapping can be customized to provide the required cable identification and signature information. This can be useful when deploying DACs with equipment that has specific cable-recognition or management requirements.