PROTECTION PRODUCTS

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PROTECTION PRODUCTS

SM712

Asymmetrical TVS Diode for

Extended Common-Mode RS-485

Description

Features

Circuit Diagram

Schematic & PIN Configuration

Revision 9/2000

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.

Applications

Mechanical Characteristics

common-mode range

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)

SOT23 (Top View)