Description

This Farsince breakout DAC converts one 400G QSFP‑DD port into four independent 100G QSFP56 copper links over a passive twinax harness. The QSFP‑DD end carries eight 50G PAM4 lanes (400GAUI‑8) and maps them as four groups of 2×50G PAM4 to each QSFP56 plug. It is engineered for short‑reach distribution from 400G aggregation or spine ports to 100G access devices such as NICs, accelerators and TOR switches in AI/HPC clusters and modern leaf/spine networks.

The passive construction introduces virtually no latency and requires no external power, while controlled‑impedance pairs and full shielding maintain low insertion loss and crosstalk. A 41 mm minimum bend radius and pull‑tab latches support clean routing and quick service in dense racks. Compliant with QSFP‑DD and QSFP56 MSA mechanics and IEEE 802.3cd electrical specs, the assembly delivers broad multi‑vendor interoperability. Farsince provides coding for major platforms, project‑specific lengths and labeling, and batch test reports to support scalable deployment and maintenance.

Specifications

• Product Type: 400G to 4×100G Passive Direct Attach Copper Breakout
• Host Interface: QSFP‑DD, 8×50G PAM4
• Device Interface: 4× QSFP56, each 2×50G PAM4 (100G)
• Cable Direction: QSFP‑DD to quad QSFP56 fan‑out
• Data Rate: 400 Gbps aggregate; 100 Gbps per leg
• Wire Gauge: 28 AWG
• Cable Structure: Shielded twinax harness, passive copper
• Minimum Bend Radius: 41 mm
• Power Design: Passive; ≤0.1 W per end for ID/EEPROM
• Operating Temperature: 0 to +70°C
• Installation: Hot‑pluggable connectors with pull‑tab latch
• Compatibility: IEEE 802.3cd 400GBASE‑CR8 and 100GBASE‑CR; QSFP‑DD & QSFP56 MSA; CMIS
• Compliance: RoHS, REACH
• Customization: Vendor coding, length and labeling options; test reports available