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PROTECTION PRODUCTS

PROTECTION PRODUCTS

SMDA05C THRU SMDA24C

Circuit Diagram

I/O Line Protection

Device Connection for Protection of Four Data Lines

The SMDAxxC series devices are designed to protect

up to four data lines. The devices are connected as

follows:

l

The SMDAxxC are bidirectional devices and are

designed for use on lines where the normal operat-

ing voltage is above and below ground. Pins 1, 2,

3, and 4 are connected to the protected lines.

Pins 5, 6, 7, and 8 are connected to ground. Since

the device is electrically symmetrical, these connec-

tions may be reversed. The ground connections

should be made directly to the ground plane for

best results. The path length is kept as short as

possible to reduce the effects of parasitic induc-

tance in the board traces.

Circuit Board Layout Recommendations for Suppres-

sion of ESD.

Good circuit board layout is critical for the suppression

of ESD induced transients. The following guidelines are

recommended:

l

Place the TVS near the input terminals or connec-

tors to restrict transient coupling.

l

Minimize the path length between the TVS and the

protected line.

l

Minimize all conductive loops including power and

ground loops.

l

The ESD transient return path to ground should be

kept as short as possible.

l

Never run critical signals near board edges.

l

Use ground planes whenever possible.

1

2

3

45

6

7

8

Ground

From Connector

To Protected

Device

Typical Connection

1

2

3

45

6

7

8

Applications Information