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PROTECTION PRODUCTS

PROTECTION PRODUCTS

SM05 THRU SM36

Applications Information

Device Schematic & Pin Configuration

Device Connection Options

The SM series is designed to protect one bidirectional

or two unidirectional data or I/O lines operating at 5 to

36 volts. Connection options are as follows:

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Bidirectional: Pin 1 is connected to the data line

and pin 2 is connected to ground (Since the device

is symmetrical, these connections may be re-

versed). For best results, the ground connection

should be made directly to a ground plane on the

board. The path length should be kept as short as

possible to minimize parasitic inductance. Pin 3 is

not connected.

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Unidirectional: Data lines are connected to pin 1

and pin 2. Pin 3 is connected to ground. For best

results, this pin should be connected directly to a

ground plane on the board. The path length should

be kept as short as possible to minimize parasitic

inductance.

Circuit Board Layout Recommendations for Suppres-

sion of ESD.

Good circuit board layout is critical for the suppression

of fast rise-time transients such as ESD. The following

guidelines are recommended (Refer to application note

SI99-01 for more detailed information):

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Place the TVS near the input terminals or connec-

tors to restrict transient coupling.

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Minimize the path length between the TVS and the

protected line.

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Minimize all conductive loops including power and

ground loops.

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The ESD transient return path to ground should be

kept as short as possible.

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Never run critical signals near board edges.

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Use ground planes whenever possible.

RS-232 Transceiver Protection Example