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www.semtech.com

PROTECTION PRODUCTS

PROTECTION PRODUCTS

TC04A-200

Protecting Multiple SLIC Lines

The TC04A-200 may be used in conjunction with

steering diodes to protect up to four SLIC Tip & Ring

line pairs. The steering diodes shunt positive surges to

ground. The internal diodes of the TC04A-200 may be

used as one of the steering diode pairs as shown. In

this configuration, each line pair may be suged to 100A

(tp=10/100µs) independantly, or all four pairs may be

surged simultaneously up to 25A (tp=10/100µs). This

provides the designer with a flexible, cost effective

solution and increased reliability over low current

protection schemes. The surge immunity of the system

may be further enhanced with the addition of line feed

resistors (LFR). These devices are used for power

cross protection and are designed to withstand light-

ning impulses per Bellcore GR-1089. Device with

resistance values ranging from of 10W - 50W are

common. A 0.1µF capacitor is recommended between

the gate & ground to speed up the triggering the

device.

Note that the sum of the loop currents must not

exceed the holding current of the TC04A-200. In the

case of four twisted pairs, the individual loop currents

would have to be limited to 50mA.

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Typical Applications