ExpressCard/54 is 54mm wide providing the same PCIe x1 and USB 2.0 interfaces as ExpressCard/34 but in a wider form factor for larger expansion cards like CompactFlash adapters and SmartCard readers.
| Pin | Name | Function | Type |
|---|---|---|---|
| 1 | GND | Ground | GND |
| 2 | USB D- | USB 2.0 data negative | BUS |
| 3 | USB D+ | USB 2.0 data positive | BUS |
| 5 | 3.3V | 3.3V supply | PWR |
| 8 | PERXP | PCIe RX positive | BUS |
| 9 | PERXN | PCIe RX negative | BUS |
| 18 | PETXP | PCIe TX positive | BUS |
| 19 | PETXN | PCIe TX negative | BUS |
| 26 | GND | Ground | GND |