Circuit Protection Considerations for USB 3.0:The ubiquitous Universal Serial Bus (USB) interface is about to undergo another evolution, keeping pace with the ever increasing demand for connectivity bandwidth. USB 3.0, or “SuperSpeed USB,” is expected to provide a major leap forward in transfer speeds, power management and flexibility. The USB 3.0 protocol was developed to provide higher data transfer rates, and increase power delivery capabilities by supporting higher current levels on each port. It includes new power management features, as well as new cables and connectors that are backward-compatible with USB 2.0 devices. The most significant change is that four additional physical copper data lines have been added in parallel with the existing USB 2.0 bus, as shown in Figure 1. These additional copper data lines are used to transmit high-speed data, but can also transmit ESD (electrostatic discharge) and other harmful voltage transients.