December 1, 2009 -- The tenfold increase in bandwidth that USB 3.0 offers consumers over USB 2.0 brings with it a variety of high-speed signaling issues that designers must address, including increased sensitivity to attenuation and jitter. At the frequencies USB 3.0 operates at, trace, connector, and cabling losses can quickly erode signal quality, making it difficult to ensure reliable communications over low-quality shielded differential pair cables. While OEMs could required the use of higher quality, thicker gauge cabling for their products, such cabling can substantially increase overall cost.

Consumers are used to not having to worry about cable quality when they connect USB devices. However, when a low-quality cable is used and performance suffers, they will often assume that the device is at fault, not their marginal hub or low-quality cables that appear to operate well enough with their other peripherals. If early adopters are disappointed with USB 3.0, this will adversely impact market uptake. Therefore, to meet the low-cost and ease-of-use expectations consumers already have for USB 3.0, developers must make maintaining signal quality a point of emphasis.

By Joseph Spisak. (Spisak is with Pericom Semiconductor Corp.)