TISP4080H3 BOURNS [Bourns Electronic Solutions], TISP4080H3 Datasheet - Page 10

• Manufacturer Part Number: TISP4080H3
• Description: BIDIRECTIONAL THYRISTOR OVERVOLTAGE PROTECTORS
• Manufacturer: BOURNS [Bourns Electronic Solutions]

Specifications are subject to change without notice.
Customers should verify actual device performance in their specific applications.
These devices are two terminal overvoltage protectors. They may be used either singly to limit the voltage between two conductors (Figure 12)
or in multiples to limit the voltage at several points in a circuit (Figure 13).
In Figure 12, 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 13, protectors Th2 and Th3 limit the maximum voltage between each conduc-
tor 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.
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.
If the impulse generator current exceeds the protector’s current rating, then a series resistance can be used to reduce the current to the
protector’s rated value to prevent possible failure. The required value of series resistance for a given waveform is given by the following
calculations. First, the minimum total circuit impedance is found by dividing the impulse generator’s peak voltage by the protector’s rated
current. The impulse generator’s fictive impedance (generator’s peak voltage divided by peak short circuit current) is then subtracted from the
minimum total circuit impedance to give the required value of series resistance. In some cases, the equipment will require verification over a
temperature range. By using the rated waveform values from Figure 11, the appropriate series resistor value can be calculated for ambient
temperatures in the range of -40 °C to 85 °C.
The protector can withstand currents applied for times not exceeding those shown in Figure 8. Currents that exceed these times must be
terminated or reduced to avoid protector failure. Fuses, PTC (Positive Temperature Coefficient) resistors and fusible resistors are overcurrent
protection devices which can be used to reduce the current flow. Protective fuses may range from a few hundred milliamperes to one ampere.
In some cases, it may be necessary to add some extra series resistance to prevent the fuse opening during impulse testing. The current versus
time characteristic of the overcurrent protector must be below the line shown in Figure 8. In some cases, there may be a further time limit
imposed by the test standard (e.g. UL 1459 wiring simulator failure).
NOVEMBER 1997 - REVISED FEBRUARY 2005
Deployment
Impulse Testing
ITU-T K.20/K 21
† FCC Part 68 terminology for the waveforms produced by the ITU-T recommendation K.21 10/700 impulse generator
AC Power Testing
GR-1089-CORE
(March 1998)
FCC Part 68
Standard
I3124
TISP4xxxH3LM Overvoltage Protector Series
Figure 12. TWO POINT PROTECTION
Peak Voltage
Setting
2500
1000
1500
1500
1000
1500
1500
4000
800
V
Th1
Waveform
10/1000
Voltage
9/720 †
9/720 †
0.5/700
10/160
10/560
10/700
2/10
µs
APPLICATIONS INFORMATION
Peak Current
Value
37.5
37.5
37.5
500
100
200
100
100
25
A
Waveform
Current
10/1000
5/320 †
5/320 †
0.2/310
10/160
10/560
5/310
2/10
µs
Figure 13. MULTI-POINT PROTECTION
25 °C Rating
TISP4xxxH3
100
500
250
160
200
200
200
200
A
Th1
Resistance
Series
Th3
Th2
Ω
0
0
0
0
0
0
0