Product Center
The OSFP-XD (Octal Small Form Factor eXtra Dense) specification was released by the OSFP MSA at Revision 1.0 in March 2023. It defines the mechanical construction, electrical interfaces, thermal management, optical Physical Medium Dependent (PMD) sublayer and management interfaces (refer also to the CMIS specification) for next-generation ultra-dense pluggable optical transceivers. Designed for data center deployment and high-speed network interconnections, the transceiver supports an aggregated port throughput up to 3.2 Tb/s per port.


Mechanical Specifications

An OSFP-XD transceiver shares the same module width as conventional OSFP, yet its internal PCB features a double-row 120-contact pinout accommodating 16 high-speed differential transmit pairs and 16 high-speed differential receive pairs. Multiple heatsink configurations can be mounted atop the module, including zipper-fin extruded aluminum sinks and open-top housings; the bottom side is configurable as a flat surface, finned airflow channel or a channel fitted with EMI spring clips. A polarization key is implemented on the rear face to prevent mismating with legacy OSFP modules. The module latches onto the host cage via dual-side latches with regulated insertion and retention forces: maximum 55 N insertion force and minimum 125 N retention force for variants with floating heatsinks. For high-power implementations, the OSFP-XD-RHS (Ride-on Heatsink) variant is specified at 10.5 mm height without on-module integrated heatsinks, which relies entirely on cage-mounted heatsinks for thermal dissipation.


Cage & Connector

Single-row surface-mount technology (SMT) connectors are deployed alongside 1×1 and 1×4 cage form factors. Each cage is pre-fitted with EMI springs, ventilation cutouts, polarization keys, stop ledges and latch springs. Detailed dimensional rules govern front-panel cutout dimensions and PCB routing layouts covering 1×1, back-to-back and 1×4 arrangements. Blank port openings must be sealed with dummy plug inserts to mitigate EMI leakage.


Electrical Interface

The 120-position edge-card connector comprises: 32 high-speed differential transmit pairs (TX[16:1]p/n), 32 differential receive pairs (RX[16:1]p/n), 8 VCC power pins rated for a combined maximum supply current of 20 A (supporting over 66 W power delivery), 40 ground pins, 4 low-speed control pins (SCL/SDA, INT/RSTn, LPWn/PRSn/ePPS), plus 4 user/vendor-defined reserved pins. Multi-level signaling is adopted for low-speed circuits to enable interrupt signaling, hardware reset, low-power mode and module presence detection, with optional ePPS/PTP reference clock support. Eight distinct power classes (Class 1 through Class 8) are defined: power consumption is capped at ≤2 W under low-power mode, while Class 8 high-power variants exceed 14 W, with stringent constraints on transient current draw.


Thermal Performance

Multiple operating case temperature grades are defined, including commercial grade (0 °C to 70 °C) and extended industrial grade (-5 °C to 85 °C). Airflow impedance curves are standardized on dedicated test fixtures, with relaxed parameters permitted for transceivers below 20 W power draw. Per EIA-364-70, the mating connector is qualified for a 10-year service life with maximum ambient temperature rise limited to 30 °C at 65 °C ambient.


Optical Interface

A broad portfolio of optical receptacle types is supported: duplex LC, MPO‑12/16, dual-row MPO‑12, MXC, dual MXC, dual Mini‑LC, dual CS, dual MDC, dual SN, dual MMC, dual SN‑MT, quad MDC, quad SN, dual MPO and 8×MDC / 8×SN interfaces. Multiple PMD block diagrams for 1600 Gb/s operation are specified including DR16, DR8, 4FR2, ZR2, 4FR4, 2FR4, 2FR8 and FR8, alongside explicit mapping between electrical lanes and optical fiber channels.
Compatibility & Reliability
Durability requirements specify 50 mating cycles for pluggable modules and 100 cycles for mating connectors and host cages. ESD compliance adheres to EN61000‑4‑2 (8 kV contact discharge, 15 kV air discharge) and 1000 V HBM ratings.


Summary

Serving as a comprehensive technical framework for ultra-high-speed pluggable transceivers spanning 1.6 Tb/s to 3.2 Tb/s, the OSFP-XD specification fully standardizes mechanical, electrical, thermal, optical and management design criteria, establishing a core foundational standard for next-generation data center networking.