![](http://datasheet.mmic.net.cn/260000/PP0640EA_datasheet_15945978/PP0640EA_5.png)
5
www.protekdevices.com
PP0640EA
thru
PP3500EC
05121.R1 4/02
APPLICATION NOTES
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
TIP
and
R
resistors are optional depending upon the TSS device
selection. Without the resistors, the PP3100EB/EC is recommended.
However, with a resistance value of 7.5 Ohms for tip and ring, the
PP3100EA 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 PPxxxxEA or EB/EC 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 PP3100EA is
recommended with a typical resistor value for tip and ring of 15
Ohms. The PP3100EB/EC 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) protection.
For analog signals, the PP3100EB/EC is recommended. With a
resistance value of 15 Ohms for the tip and ring resistors, the
PP3100EA 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