WEITRON

http://www.weitron.com.tw

5/7

19-Apr-07

SLVU2.8

Application Note

Unidirectional Common-Mode Protection (Fig.9)

The SLVU2.8 provides one line of unidirectional protection

in a common-mode configuration as depicted in figure 9.

Circuit connectivity is as follows:

Line 1 is connected to Pin 3

Pins 1 and 2 are connected to ground

Bidirectional Common-Mode Protection (Fig.10)

Two SLVU2.8 devices provide one line of bidirectional

protection in a common-mode configuration as depicted

in fig.10

Circuit connectivity is as follows:

* Line 1 is connected to Pin1 of Device 1 & Pin 2 of Device 2

* Pin 2 of Device 1 and Pin 1 of Device 2 are connected to ground

* Pin 3 of both devices is not connected

Bidirectional Differential-Mode Protection (Fig.11)

Circuit connectivity is as follows:

* Line 1 is connected to Pin1 of Device 1 & Pin 2 of Device 2

* Line 2 is connected to Pin 2 of Device 1 & Pin 1 of Device 2

Fig.9

Fig.10

Fig.11

The SLVU2.8 is ideal for providing protection for electronic equipment that is susceptible to damage

caused by Electrostatic Discharge (ESD), Electrical Fast Transients (EFT) and tertiary lightning effects.

This product is offered in a unidirectional configuration and provides both commonmode or

differential-mode protection.

Circuit Board Layout Protection

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.

Two SLVU2.8 devices provide up to two lines of

bidrectional protection in a differenitalmode configuration

as depicted in fig.11