TISP4360H3BJ
BIDIRECTIONAL THYRISTOR OVERVOLTAGE PROTECTORS
JUNE 1999
APPLICATIONS INFORMATION
deployment
These devices are two terminal overvoltage protectors. They may be used either singly to limit the voltage
between two conductors (Figure 11) or in multiples to limit the voltage at several points in a circuit (Figure 12).
Th3
Th1
Th1
Th2
Figure 11. TWO POINT PROTECTION
Figure 12. MULTI-POINT PROTECTION
In Figure 11, protector Th1 limits the maximum voltage between the two conductors to ±V
(BO)
. This
configuration is normally used to protect circuits without a ground reference, such as modems. In Figure 12,
protectors Th2 and Th3 limit the maximum voltage between each conductor and ground to the ±V
(BO)
of the
individual protector. Protector Th1 limits the maximum voltage between the two conductors to its ±V
(BO)
value. If the equipment being protected has all its vulnerable components connected between the conductors
and ground, then protector Th1 is not required.
impulse testing
To verify the withstand capability and safety of the equipment, standards require that the equipment is tested
with various impulse wave forms. The table below shows some common values.
PEAK VOLTAGE
STANDARD
SETTING
V
GR-1089-CORE
2500
1000
1500
FCC Part 68
(March 1998)
I3124
ITU-T K20/K21
800
1500
1000
1500
1500
4000
VOLTAGE
WAVE FORM
µs
2/10
10/1000
10/160
10/560
9/720 †
9/720 †
0.5/700
10/700
PEAK CURRENT
VALUE
A
500
100
200
100
37.5
25
37.5
37.5
100
CURRENT
WAVE FORM
µs
2/10
10/1000
10/160
10/560
5/320 †
5/320 †
0.2/310
5/310
TISP4360H3BJ
25 °C RATING
A
500
100
250
160
200
200
200
200
SERIES
RESISTANCE
Ω
0
0
0
0
0
0
0
† FCC Part 68 terminology for the waveforms produced by the ITU-T recommendation K21 10/700 impulse generator
Series resistance can be added to cover situations where either the TISP4360H3BJ current rating will be
exceeded or excessive wiring currents result or both.
When a primary protector is used, the TISP4360H3BJ may operate before the primary protector. With the
TISP460H3BJ in a low voltage state, the primary protector is prevented from working. High currents, which
should have been carried by the primary protector, now flow through the wiring to the equipment and through
the TISP4360H3BJ. Interference and network equipment damage can occur, particularly if the currents are
diverted to the local ground. Protector co-ordination prevents this problem. A series resistor can be used to
develop a voltage drop large enough to activate the primary protector. If the primary protector was a gas
discharge tube (GDT) with a maximum d.c. sparkover of 400 V and the typical lightning impulse decay time
was several hundred microseconds (TISP4360H3BJ rating 200 A), a 2
Ω
series resistor (400 V/200 A) would
PRODUCT
8
INFORMATION
POINN [ POWER INNOVATIONS LTD ]
