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PROTECTION PRODUCTS

SMF05 & SMF12

SMF Circuit Diagram

Protection of Four Unidirectional Lines

Device Connection for Protection of Four Data Lines

The SMFxx is designed to protect up to four unidirec-

tional data lines. The device is connected as follows:

1. Unidirectional protection of four I/O lines is

achieved by connecting pins 1, 3, 4, and 5 to the

data lines. Pin 2 is connected to ground. The

ground connection 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 inductance 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 SMFxx near the input terminals or con-

nectors to restrict transient coupling.

l

Minimize the path length between the SMSxx 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.

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Applications Information