USB 3.0

This entry details the new USB 3.0 standard, with an emphasis on it’s 2.0 standard.

The new USB standard, published at the end of last year and expected to first hit markets at the end of 2009 or early 2010, is a significant improvement over the previous and current version, 2.0. USB 3.0, dubbed “Super-Speed” (as opposed to the previous “High-Speed”), has several important features that will allow it to be adapted into the marked. Probably one of the most important features is backwards compatibility: All current 2.0 devices are usable with the new system. This is accomplished by making two sub systems: one is the 3.0, and one is the 2.0. The two systems are pin compatible, so they share the same USB port. Any 2.0 will be usable with 3.0, and vice versa.

Probably the most notable difference with the new standard is the high speed: 5Gbits/s! Compared to the previous 480 Mbits/s, the speed increase is substantial. The increase is accomplished by adding four more wires to the cable. This will make 3.0 cables substantially larger than the previous 2.0 version, enough so that the different cables can be visually separated.

Another notable change is in the power delivery capabilities of the system. In the prior version, 2.0, devices were guaranteed a maximum of 500 ma, with more negotiable. The threshold has now been raised to 900 ma, with more negotiable. The increase is in recognition of the fact that more and more embedded systems are using USB to charge batteries.

Source: “USB 3.0 SuperSpeed” by José Luis Rupérez Fombellida, published in the May 2009 elector.

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