5

05081.R10 2/07

www.protekdevices.com

PP0640SA

thru

PP3500SC

APPLICATION NOTE

FIGURE 1: UL 1459 & FCC Part 68 - Metallic Protection

The TSS (Thyristor Surge Suppressor) device is located across the

tip-to-ring after a limiting resistor and fuse combination. R

R

tion. Without the resistors, the PP3100SB/SC is recommended.

However, with a resistance value of 7.5 Ohms for tip and ring, the

PP3100SA is recommended. Digital signals may use a lower TSS

device depending upon the total tip to ring voltage range. Selection

of the TSS device, either PPxxxxSA or SB/SC is based upon the

value of the tip and ring resistors. For the National Electric Code

(NEC) article 800, it is recommended that at least one fuse be used

in the tip or ring line for metallic surges. Fuses may be replaced with

a suitable Positive Temperature Coefficient (PTC) automatic

resettable current limiting device.

FIGURE 2 - UL 1459 & FCC Part 68 - Longitudinal Protection

There are two TSS devices, one located from tip-to-ground and one

ring-to-ground. For standard analog signals, the PP3100SA is

recommended with a typical resistor value for tip and ring of 15

Ohms. The PP3100SB/SC is recommended for resistor values of 7.5

Ohms each. The National Electric Code (NEC) article 800 requires

two fuse elements when connecting to ground. Fuses or a suitable

Positive Temperature Coefficient (PTC) automatic resettable current

limiting device may be used. The purpose of this circuit is to limit AC

power current from getting on the ground line causing any safety

hazard.

FIGURE 3 - UL 1459 & FCC Part 68 - Metallic & Longitudinal

Protection

Three equal TSS devices are used in this application for metallic (tip-

to-ring) and longitudinal (tip-to-ground and ring-to-ground) protec-

tion. For analog signals, the PP3100SB/SC is recommended. With a

resistance value of 15 Ohms for the tip and ring resistors, the

PP3100SA may be used. The National Electric Code (NEC) article

800 requires two fuse elements when connecting to ground. Fuses

or a suitable Positive Temperature Coefficient (PTC) automatic

resettable current limiting device may be used. This circuit is

recommended for protection against the Bellcore requirement: First

Level Lightning Surge Tests (Telecommunications Port), document #

GR-1089-CORE.

Fuse

TIP

R

Tip

RING

To

Protected

Equipment

R

Ring

FIGURE 1 - Metallic Protection

Tip

R

To

Protected

Equipment

Ring

R

TIP

RING

FIGURE 2 - Longitudinal Protection

Tip

R

To

Protected

Equipment

Ring

R

TIP

RING

FIGURE 3 - Metallic & Longitudinal Protection