Front Panel I/O Connectivity Design Guide

• Provides protection to the motherboard in the case where the front panel cable is cut or

damaged during assembly or manufacturing resulting in a short between the USBPWR and

ground.

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NOTE

Ensure that fuse elements are not present on both the motherboard and the cabled solution.

Having fuse elements in both locations results in a voltage drop at the USB connector, which may

make the USB 2.0 solution non-compliant.

3.2.8.2 USBPWR Bypass Capacitance

Refer to the USB 2.0 Specification for details on the power distribution requirements. Voltage drop

and droop testing procedures are also available at:

http://www.usb.org/developers/

3.2.8.3 Filter Components

Filtering must be carefully addressed to ensure that the system meets EMC requirements.

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NOTE

Ensure that filter components are not present on both the motherboard and the cable solution.

Systems with filter elements in both locations may not meet the USB Specification signal quality

requirements.

3.2.8.4 ESD Components

ESD suppression components should be included to ensure that the system meets applicable ESD

requirements.

3.2.8.5 Motherboard Power Requirements

See the USB 2.0 specification for the voltage and current requirements that must be maintained at

the front panel interface board’s USB connector.

3.2.8.6 Motherboard Signal Quality Requirements

The signal quality as measured at the USB front panel connectors must meet the requirements given

in the most recent USB Specification.

White papers describing the signal quality compliance testing procedures for USB Low Speed and

Full Speed signaling performed at USB Plugfests are available. See Section 1.1, page 11 for

additional information.

A design guide for integrating a discrete USB 2.0 host controller onto a four-layer desktop

motherboard is also available. See Section 1.1, page 11 for additional information.