TISP7180F3D-S Bourns Inc., TISP7180F3D-S Datasheet - Page 15

• Manufacturer Part Number: TISP7180F3D-S
• Description: Sidacs Triple Element Bidirectional
• Manufacturer: Bourns Inc.

Specifications of TISP7180F3D-S

• Breakover Current Ibo Max: 4.3 A
• Rated Repetitive Off-state Voltage Vdrm: 145 V
• Off-state Leakage Current @ Vdrm Idrm: 0.01 mA
• Forward Voltage Drop: 5 V
• Mounting Style: SMD/SMT
• Package / Case: SO-8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

With the generator output open circuit, when SW closes, C 1 discharges through R 1 . The decay time constant will be C 1 R 1 , or 20 x 50 =
1000 µs. For the 50 % voltage decay time, the time constant needs to be multiplied by 0.697, giving 0.697 x 1000 = 697 µs which is rounded to
700 µs.
The output rise time is controlled by the time constant of R 2 and C 2 , which is 15 x 200 = 3000 ns or 3 µs. Virtual voltage rise times are given
by straight line extrapolation through the 30 % and 90 % points of the voltage waveform to zero and 100 %. Mathematically, this is equivalent to
3.24 times the time constant, which gives 3.24 x 3 = 9.73 which is rounded to 10 µs. Thus, the open circuit voltage rises in 10 µs and decays in
700 µs, giving the 10/700 generator its name.
When the overvoltage protector switches, it effectively shorts the generator output via the series 25 Ω resistor. Two short circuit conditions
need to be considered: single output using R 3 only (top circuit of Figure 33) and dual output using R 3 and R 4 (bottom circuit of Figure 33).
For the single test, the series combination of R 2 and R 3 (15 + 25 = 40 Ω) is in shunt with R 1 . This lowers the discharge resistance from 50 Ω to
22.2 Ω, giving a discharge time constant of 444 µs and a 50% current decay time of 309.7 µs, which is rounded to 310 µs.
For the rise time, R 2 and R 3 are in parallel, reducing the effective source resistance from 15 Ω to 9.38 Ω, giving a time constant of 1.88 µs.
Virtual current rise times are given by straight line extrapolation through the 10 % and 90 % points of the current waveform to zero and 100 %.
Mathematically, this is equivalent to 2.75 times the time constant, which gives 2.75 x 1.88 = 5.15, which is rounded to 5 µs. Thus, the short
circuit current rises in 5 µs and decays in 310 µs, giving the 5/310 wave shape.
The series resistance from C 1 to the output is 40 Ω, giving an output conductance of 25 A/kV. For each 1 kV of capacitor charge voltage, 25 A
of output current will result.
For the dual test, the series combination of R 2 plus R 3 and R 4 in parallel (15 + 12.5 = 27.5 Ω) is in shunt with R 1 . This lowers the discharge
resistance from 50 Ω to 17.7 Ω, giving a discharge time constant of 355 µs and a 50% current decay time of 247 µs, which is rounded to
250 µs.
For the rise time, R 2 , R 3 and R 4 are in parallel, reducing the effective source resistance from 15 Ω to 6.82 Ω, giving a time constant of 1.36 µs,
which gives a current rise time of 2.75 x 1.36 = 3.75, which is rounded to 4 µs. Thus, the short circuit current rises in 4 µs and decays in 250
µs, giving the 4/250 wave shape.
Lightning Surge (continued)
ITU-T 10/700 Generator (continued)
TISP7xxxF3 (MV, HV) Overvoltage Protector Series
20 µF
C
1
2.8 kV
V
C
10/700 GENERATOR - SINGLE TERMINAL PAIR TEST
SW
50
R
1
Ω
20 µF
C
1
5.2 kV
V
C
15 Ω
10/700 GENERATOR - DUAL TERMINAL PAIR TEST
R
2
200 nF
SW
C
2
50
R
1
Ω
APPLICATIONS INFORMATION
15
R
2
Ω
200 nF
C
2
25
R
Figure 33.
3
Ω
5/310
70 A
5/310
70 A
T AND G
T
TEST
Customers should verify actual device performance in their specific applications.
25
25
R
R
G
3
Ω
4
Ω
R
4/250
190 A
4/250
95 A
T AND G,
R AND G
T
DUAL
R AND G
TEST
R
4/250
95 A
TEST
G
G
Specifications are subject to change without notice.
R
T
MARCH 1994 - REVISED SEPTEMBER 2008
R AND T
R
TEST
T
G