USB 3.0 Cable Interface
[USB Interface ICs]
[USB Pinout] [USB Connector]
[USB Standard / Organizations]
[Converter, Adapter, Cables] [Software]
This page covers USB 3.0, refer here for USB 2.0
The USB 3.0 specification is the combination of the physical SuperSpeed bus combined in parallel with the physical USB 2.0 bus.
The cable has the original 4 wires of the USB 2.0 specification [D+/D-, Power & Ground] plus the one added by the USB 3.0 specification.
The USB 3.0 specification adds two sets of Shielded Differential Paired wires [labeled as SDP].
Each shielded pair includes its own drain wire, one for each pair; however both drain wires are attached to a single pin on the connector.
The actual wire gauges used in the cable are not specified directly, but a range is provided.
This way the OEM [Original Equipment Manufacturer] can decide between increased signaling loss or increased cable flexibility.
The main power and ground wires should use wires of between 20 and 28 gauge.
The Unshielded Twisted Pair [UTP] wires of USB 2.0 should use wires in the range between 28 and 34 gauge.
The two sets of differential wire pars added under USB 3.0 should use a wire gauge of between 26 and 34.
Their drain wire should have a wire gauge of between 28 and 34 AWG.
Of course changing the gauge of the different wires also changes the outer diameter of the cable, which should range from 3mm to 6mm.
The wire is color coded per the drawing above, the Drain Wire is by definition uninsulated.
The braid should be terminated on the metal shell of the connector. [the coverage does not seem to be specified]
Cables will have an A plug on one end an a B plug on the opposite end.
The maximum cable length is not specified in the document, length is defined as still meeting the other electrical requirements.
The USB interface is designed to operate down to -20 degrees C.
The standard A connector is depicted, not shown is the standard B connector.
The power B is also not shown, as well as the Micro-A, Micro-B or the Micro-AB styles.
Note the two drain wires have a common connection point on the connector [GND_Drain].
USB Revision 3.0 type A Connector
Note the only change between the standard-A and standard-B are the SuperSpeed lines.
The SSRX lines swap positions with the SSTX lines, so the receiver connects with the transmitter.
For reference here is revision 2.0, USB type A Connector