TISP7xxxH3SL Overvoltage Protector Series
APPLICATIONS INFORMATION
Deployment
These devices are three terminal overvoltage protectors. They limit the voltage between three points in the circuit. Typically, this would be the
two line conductors and protective ground (Figure 11).
Th3
Th1
Th2
Figure 11. MULTI-POINT PROTECTION
In Figure 11, 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.
Manufacturers are being increasingly required to design in protection coordination. This means that each protector is operated at its design
level and currents are diverted through the appropriate protector, e.g. the primary level current through the primary protector and lower levels
of current may be diverted through the secondary or inherent equipment protection. Without coordination, primary level currents could pass
through the equipment only designed to pass secondary level currents. To ensure coordination happens with fixed voltage protectors, some
resistance is normally used between the primary and secondary protection. The values given in this data sheet apply to a 400 V (d.c.
sparkover) gas discharge tube primary protector and the appropriate test voltage when the equipment is tested with a primary protector.
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.
Standard
Peak Voltage
Setting
V
Voltage
Peak Current
Value
A
Current
Waveform
µs
TISP7xxxH3
25
°C
Rating
A
Series
Resistance
Ω
Coordination
Resistance
(Min.)
NA
Waveform
µs
2500
2/10
500
2/10
500
GR-1089-CORE
0
1000
10/1000
100
10/1000
100
1500
10/160
200
10/160
250
800
10/560
100
10/560
130
FCC Part 68
0
9/720 †
25
5/320 †
200
1000
(March 1998)
1500
(SINGLE)
37.5
5/320 †
200
1500
(DUAL)
2 x 27
4/250
2 x 225
I 31-24
1500
0.5/700
37.5
0.2/310
200
0
200
5/310
25
10/700
1000
200
5/310
37.5
(SINGLE)
1500
0
ITU-T K.20/K.21
200
5/310
100
(SINGLE)
4000
2 x 225
4/250
2 x 72
(DUAL)
4000
† FCC Part 68 terminology for the waveforms produced by the ITU-T recommendation K.21 10/700 impulse generator
NA = Not Applicable, primary protection removed or not specified.
NA
NA
NA
NA
4.5
6.0
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 10, the appropriate series resistor value can be calculated for ambient
temperatures in the range of -40
°C
to 85
°C.
MARCH 1999 - REVISED FEBRUARY 2005
Specifications are subject to change without notice.
Customers should verify actual device performance in their specific applications.
BOURNS [ BOURNS ELECTRONIC SOLUTIONS ]
