AN2456

SLIC protection

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Figure 12.

-800 V - 100 A (2/10 µs) - Metallic on tip - ANP mode

Figure 11 and Figure 12 show the behavior of the protection for positive and negative

surges in Ringing mode and ANP mode respectively. The lightning surge is applied in

metallic configuration and is 2/10 µs – 800 V – 100 A per the Telcordia GR1089 Intrabuilding

standard. In both cases it is seen that the peak current is only about 40 A. This is because of

the two 10

Ω resistors on the line (800 V/ (8 Ω +10 Ω) ~ 40 A).

In the case of Figure 11 it is seen that the diode of the LCP1521S on the Ring wire clamps

the voltage to GND when a positive surge is applied to RING. The protection behavior would

be similar if the surge was applied on TIP. We also see that there is little effect of the surge

Figure 12 shows that the thyristor structure inside the LCP1521S on the TIP wire fires when

thyristor drops below its holding current, the voltage on TIP returns to the operating voltage.

Figure 13.

+1500 V - 100 A (2/10 µs) - longitudinal - ANP mode

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