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SuperSpeed USB 3.0 Specification

Author: Sanjiv Kumar, Director of Verification IP Products

[image] Sanjiv Kumar

The Universal Serial Bus (USB) 3.0 specification is a new industry-standard peripheral connection technology, developed by USB Implementers Forum, for connecting peripherals to PCs and laptops. The USB 3.0 specification draws from the same architecture of the wired USB specification and therefore is a backward-compatible standard with the same ease-of-use and plug and play capabilities of previous USB technologies, but with a 10X performance increase and lower power consumption. The USB 3.0 specification uses two additional high-speed differential pairs for SuperSpeed mode, which boosts its bandwidth to 5 GB/s.

For end-users of the USB 3.0 specification, the goals of connecting peripherals with PCs or laptops are still the same as the Hi-Speed (USB 2.0) specification, but with significantly increased speed and reduced power consumption. The SuperSpeed USB specification, therefore, is not simply an upgrade to earlier versions of the USB 2.0 specification. Due to the broad deployment of USB 2.0 devices in the market, SuperSpeed USB devices need to be backward compatible, but the backward compatibility portion of the SuperSpeed USB specification targets only the device drivers and connector architecture. The higher speed and reduced power consumption for the USB 3.0 specification uses advanced mechanisms and techniques similar to ones that were used for other high bandwidth interfaces, such as the PCI Express (PCIe) specification. As a result, the SuperSpeed USB specification has many differences compared to earlier generations of USB specifications (1.1/2.0/OTG).

The scope of this paper is to clearly explain some of the key differences between the new USB 3.0 specification and earlier USB generations. Additionally, this article identifies the main similarities between USB 3.0 and PCI Express (PCIe).

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