4

www.protekdevices.com

05205.R0 4/05

USB0403

thru

USB0424C

APPLICATION NOTE

CIRCUIT BOARD LAYOUT RECOMMENDATIONS

Circuit board layout is critical for Electromagnetic

Compatibility (EMC) protection. The following

guidelines are recommended:

✔

The protection device should be placed near the

input terminals or connectors, the device will

divert the transient current immediately before it

can be coupled into the nearby traces.

✔

The path length between the TVS device and the

protected line should be minimized.

✔

All conductive loops including power and ground

loops should be minimized.

✔

The transient current return path to ground

should be kept as short as possible to reduce

parasitic inductance.

✔

Ground planes should be used whenever

possible. For multilayer PCBs, use ground vias.

The USB04 Series are TVS arrays designed to protect I/O or data lines from the damaging effects of ESD and EFT. This product series provides

both unidirectional and bidirectional protection, with a surge capability of 350 Watts P

UNIDIRECTIONAL COMMON-MODE CONFIGURATION (Figure 1)

The two USB04 Series devices provide protection in a common-mode

configuration as depicted in Figure 1.

Circuit connectivity is as follows:

✔

TVS Device 1: Line 1(D+) is connected to Pins 2 & 3.

✔

TVS Device 2: Line 2(D-) is connected to Pins 2 & 3.

✔

Both TVS Devices: Pins 1 & 4 connected to ground.

BIDIRECTIONAL DIFFERENTIAL-MODE CONFIGURATION (Figure 2)

The USB04xxC Series provides protection in a differential-mode configuration

as depicted in Figure 2.

Circuit connectivity is as follows:

✔

Line 1(R

✔

Line 2(T

Figure 1 - Unidirectional Configuration (Two TVS Devices)

Common-Mode USB Protection

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1

4

3

2

1

4

2

3

D+

USB IC

D-

GND

SOLDER PAD

Figure 2 - Bidirectional Configuration

Differential-Mode Ethernet Protection

1

4

3

2

R

R

T

X

R

X