SM05 THRU SM36
PROTECTION PRODUCTS
Applications Information
Device Connection Options
Device Schematic & Pin Configuration
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.
RS-232 Transceiver Protection Example
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.
Minimize the path length between the TVS and the
protected line.
Minimize all conductive loops including power and
ground loops.
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.
Use ground planes whenever possible.
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