USB 2SigmaTel Hardware Introduction 2005 4/28/05 SigmaTel Confidential 1 USB Layout Consideration High Speed USB Platform Design Guidelines Some Common Routing Mistakes 4/28/05 SigmaTel Confidential 2 USB Layout Consideration High Speed USB Platform Design Guidelines Below figure provides an illustration of the recommended trace spacing. 4/28/05 SigmaTel Confidential 3 USB Layout Consideration Maintain parallelism between USB differential signals with the trace spacing needed to achieve 90ohms differential impedance. Deviations will normally occur due to package breakout and routing to connector pins. Just ensure the amount and length of the deviations are kept to the minimum possible. Use an impedance calculator to determine the trace width and spacing required for the s……