QSFP-DD (Quad SFP Double Density) doubles the QSFP28 density to 8 lanes for 400 Gbps. Backward compatible with QSFP28 modules. The dominant 400GbE form factor in data centers and carrier networks.
| Pin | Name | Function | Type |
|---|---|---|---|
| 1 | GND | Ground | GND |
| 2 | TX7n | TX lane 7 negative | BUS |
| 3 | TX7p | TX lane 7 positive | BUS |
| 4 | TX5n | TX lane 5 negative | BUS |
| 5 | TX5p | TX lane 5 positive | BUS |
| 8 | MOD_SEL# | Module select | I/O |
| 9 | RESET# | Module reset | I/O |
| 10 | VCC | 3.3V supply | PWR |
| 14 | RX6p | RX lane 6 positive | BUS |
| 15 | RX6n | RX lane 6 negative | BUS |
| 22 | VCC | 3.3V supply | PWR |