USB 3.0 Circuit Protection
USB 3.0 devices incorporate four additional data channels providing 5Gbps communication speeds and the power bus has been up-rated to 900mA maximum current. These new USB 3.0 specifications, combined with continuous shrinkage of integrated chip geometries, make protection against electrical transients and overcurrent faults more critical and more complicated. The threats of damage are higher, even from smaller electrostatic discharges (ESDs), as well as from short circuit events.Understanding key selection criteria and tradeoffs between protection technologies (PTCs, varistors, polymer and silicon-based devices) is key to achieving a successful design. This application note explains factors and issues that require consideration in detail.