SM712 Datasheet, PDF (1/6 Pages) Semtech Corporation – Asymmetrical TVS Diode for Extended Common-Mode RS-485

PROTECTION PRODUCTS
Description
The SM712 transient voltage suppressor (TVS) diode is
designed for asymmetrical (12V to -7V ) protection in
multi-point data transmission standard RS-485 applica-
tions. The SM712 may be used to protect devices
from transient voltages resulting from electrostatic
discharge (ESD), electrical fast transients (EFT), and
lightning.
The SM712 features 400 Watts (tp = 8/20µs) of
power handling capability to accommodate the higher
transient voltage levels which may be expected in
extended common mode applications. This provides
higher equipment reliability and eliminates the “guess
work” required when using zener diodes that are not
rated to handle such transient conditions.
The SM712 replaces four discrete components by
integrating two 12V and two 7V TVS diodes in a single
package. The integrated design aids in reducing
voltage over-shoot associated with trace inductance.
The low clamping voltage of the SM712 minimizes the
stress on the protected transceiver. The SOT23
package allows flexibility in the design of “crowded”
circuit boards.
SM712
Asymmetrical TVS Diode for
Extended Common-Mode RS-485
Features
u 400 watts peak pulse power (tp = 8/20µs)
u Transient protection for asymmetrical data lines to
IEC 61000-4-2 (ESD) 15kV (air), 8kV (contact)
IEC 61000-4-4 (EFT) 40A (t5/50ns)
IEC 61000-4-5 (Lightning) 12A (8/20µs)
u Protects two +12V to -7V lines
u Low capacitance
u Low clamping voltage
u Solid-state silicon avalanche technology
Mechanical Characteristics
u JEDEC SOT23 package
u Molding compound flammability rating: UL 94V-0
u Marking : 712
u Packaging : Tape and Reel per EIA 481
Applications
u Protection of RS-485 transceivers with extended
common-mode range
u Security systems
u Automatic Teller Machines
u HFC systems
u Networks
Circuit Diagram
Schematic & PIN Configuration
Revision 9/2000
SOT23 (Top View)
1
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