TISP7072F3, TISP7082F3
TRIPLE BIDIRECTIONAL THYRISTOR OVERVOLTAGE PROTECTORS
MARCH 1994 - REVISED MARCH 2000
PEAK VOLTAGE
SETTING
V
VOLTAGE
WAVE FORM
µs
PEAK CURRENT
CURRENT
TISP7xxxF3
SERIES
COORDINATION
RESISTANCE
Ω (MIN.)
STANDARD
VALUE
A
WAVE FORM 25 °C RATING RESISTANCE
µs
A
2 x 85
2 x 40
65
Ω
2500
2/10
2 x 500
2 x 100
200
2/10
GR-1089-CORE
25
NA
1000
10/1000
10/160
10/1000
10/160
10/560
5/320 †
5/320 †
4/250
1500
16
10
800
10/560
100
45
FCC Part 68
(March 1998)
1000
9/720 †
(SINGLE)
(DUAL)
0.5/700
10/700
25
50
NA
1500
37.5
2 x 27
37.5
25
50
0
1500
2 x 60
50
I 31-24
1500
0.2/310
5/310
0
0
NA
NA
NA
8
1000
50
1500
(SINGLE)
(SINGLE)
(DUAL)
37.5
100
5/310
50
0
ITU-T K20/K21
4000
5/310
50
40
12
4000
2 x 72
4/250
2 x 60
7
† FCC Part 68 terminology for the waveforms produced by the ITU-T recommendation K21 10/700 impulse generator
NA = Not Applicable, primary protection removed or not specified.
If the impulse generator current exceeds the protectors current rating then a series resistance can be used to
reduce the current to the protectors rated value and so 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 generators peak voltage by the protectors rated current. The
impulse generators fictive impedance (generators 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 derated waveform values
from the thermal information section, the appropriate series resistor value can be calculated for ambient
temperatures in the range of 0 °C to 70 °C.
protection voltage
The protection voltage, (V
), increases under lightning surge conditions due to thyristor regeneration. This
(BO)
®
increase is dependent on the rate of current rise, di/dt, when the TISP is clamping the voltage in its
breakdown region. The V value under surge conditions can be estimated by multiplying the 50 Hz rate
(BO)
V
(250 V/ms) value by the normalised increase at the surge’s di/dt. An estimate of the di/dt can be made
(BO)
from the surge generator voltage rate of rise, dv/dt, and the circuit resistance.
As an example, the ITU-T recommendation K.21 1.5 kV, 10/700 surge has an average dv/dt of 150 V/µs, but,
as the rise is exponential, the initial dv/dt is three times higher, being 450 V/µs. The instantaneous generator
output resistance is 25 Ω. If the equipment has an additional series resistance of 20 Ω, the total series
resistance becomes 45 Ω. The maximum di/dt then can be estimated as 450/45 = 10 A/µs. In practice the
measured di/dt and protection voltage increase will be lower due to inductive effects and the finite slope
®
resistance of the TISP breakdown region.
capacitance
off-state capacitance
The off-state capacitance of a TISP is sensitive to junction temperature, T , and the bias voltage,
®
J
comprising of the dc voltage, V , and the ac voltage, V . All the capacitance values in this data sheet are
D
d
measured with an ac voltage of 1 V rms. When V >> V the capacitance value is independent on the value
D
d
of V . Up to 10 MHz the capacitance is essentially independent of frequency. Above 10 MHz the effective
d
capacitance is strongly dependent on connection inductance. For example, a printed wiring (PW) trace of
10 cm could create a circuit resonance with the device capacitance in the region of 80 MHz.
P R O D U C T
I N F O R M A T I O N
15
POINN [ POWER INNOVATIONS LTD ]
