Thyristor Surge Suppressors

P0060~P3500SA_B_C Series

Figure 1.E

xamples of protection stages for line cards

In such a stage, parallel function is assumed by one or several Trisil, and is used to protect

against short duration surge (lightning). During this kind of surges the Trisil limits the voltage

across the device to be protected at its break over value and then fires. The fuse assumes

the series function, and is used to protect the module against long duration or very high

current mains disturbances (50/60Hz). It acts by safe circuit opening. Lightning surge and

mains disturbance surges are defined by standards like GR1089, FCC part 68, ITU-T K20.

Figure 2. Typical circuits

Line

Ring

relay

Line

l

a

n

i

m

r

e

t

r

o

d

r

a

c

e

n

il

L

S

D

x

.

x

E

d

r

a

c

e

n

il

g

o

l

a

n

A

.

x

E

Fuse TCP 1.25A

T1

T2

Typical circuit for subscriber side

Fuse TCP 1.25A

Tip S

Gnd

Ring S

Fuse TCP 1.25A

Tip L

Gnd

Ring L

Typical circuit for central office side

4