Samsung RT55EANS Spécifications télécharger pdf (Page 95)

Ref# 420826 Intel

Atom™ processor CE4100 95

Platform Design Guide

Intel Confidential

8.2.1.1 USB 2.0 Trace Separation

Use the following separation guidelines.

• Maintain parallelism between USB differential signals with the trace spacing needed to

achieve 90-Ω differential impedance. Deviations will normally occur due to package

breakout and routing to connector pins. Just ensure the amount and length of the

deviations is kept to the minimum possible.

• Use an impedance calculator to determine the trace width and spacing required for the

specific board stack-up being used. 4-mil traces with 4-mil spacing results in

approximately 90 Ω differential trace impedance.

• Minimize the length of high-speed clock and periodic signal traces that run parallel to

high-speed USB signal lines, to minimize crosstalk. Based on EMI testing experience, the

minimum suggested spacing to clock signals is 50 mils.

• Based on simulation data, use 20-mil minimum spacing between high-speed USB signal

pairs and use other signal traces for optimal signal quality. This helps to prevent

crosstalk.

Figure 8-6. Recommended USB Trace Spacing

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Samsung RT55EANS Spécifications Page 95