10 Layout

10.1 Layout Guidelines

• The optimum placement is as close to the connector as possible.

– EMI during an ESD event can couple from the trace being struck to other nearby unprotected traces,

resulting in early system failures.

– The PCB designer must minimize the possibility of EMI coupling by keeping any unprotected traces away

from the protected traces which are between the TVS and the connector.

• Route the protected traces as straight as possible.

• Eliminate any sharp corners on the protected traces between the TVS and the connector by using rounded

corners with the largest radii possible.

– Electric fields tend to build up on corners, increasing EMI coupling.

10.2 Layout Example

USB2.0 Connector

Pin to GND

Legend

GND

VBUS

To power supply

To USB transceiver

D+

D-

ESD321

ESD321

Figure 10-1. USB 2.0 ESD Layout

ESD321

SLVSEN8A – JULY 2018 – REVISED DECEMBER 2022

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