CA Datasheet, PDF (3/8 Pages) Littelfuse – Varistor Products - High Energy Industrial Disc

Varistor Products
High Energy Industrial Disc
CA Varistor Series
Device Ratings and Specifications (continued)
MAXIMUM RATINGS (85 ^oC)
SPECIFICATIONS (25^oC)
CONTINUOUS
TRANSIENT
MODEL
NUMBER
SIZE
(mm)
V_RMS
V_M(AC)
(V)
V_DC
V_M(DC)
(V)
ENERGY
(2ms)
W_TM
(J)
PEAK
CURRENT
(8/20µs)
I_TM
(A)
VARISTOR VOLTAGE AT
1mA DC TEST CURRENT
MIN
V_N(DC)
MAX
(V)
(V)
(V)
MAX
CLAMPING
VOLT V_C AT
200A
CURRENT
(8/20µs)
V_C
(V)
TYPICAL
CAPACI-
TANCE
f = 1MHz
(pF)
V751CA32
32
750
970
V751CA40
40
V751CA60
60
700
1050
2600
25000
40000
70000
1080
1200
1320
2050
2000
1880
800
1800
3500
V881CA60
60
880
1150
3200
70000
1290
1500
1650
2340
2700
V112CA60
V142CA60
V172CA60
V202CA60
V242CA60
V282CA60
60
1100
1400
60
1400
1750
60
1700
2150
60
2000
2500
60
2400
3000
60
2800
3500
3800
5000
6000
7500
8600
10000
70000
70000
70000
70000
70000
70000
1620
2020
2500
2970
3510
4230
1800
2200
2700
3300
3900
4700
2060
2550
3030
3630
4290
5170
2940
3600
4300
5200
6200
7400
2200
1800
1500
1200
1000
800
NOTE: Average power dissipation of transients not exceed 1.5W, 2.0W and 2.5W for model 32mm, 40mm and 60mm, respectively.
1. Peak current applies to applications rated up to 115V_RMS. Peak Current is 30kA for applications greater than 115V_RMS.
2. Peak current applies to applications rated up to 132V_RMS. Peak Current is 30kA for applications greater than 132V_RMS.
Power Dissipation Ratings
Should transients occur in rapid succession, the average power
dissipation result is the energy (watt-seconds) per pulse times the
number of pulses per second. The power so developed must be within
the specifications shown on the Device Ratings and Specifications table
for the specific device. Furthermore, the operating values need to be
derated at high temperatures as shown in Figure 1. Because varistors
can only dissipate a relatively small amount of average power they are,
100
therefore, not suitable for repetitive applications that involve substantial
90
amounts of average power dissipation.
100
90
80
70
60
50
40
30
20
10
0
-55 50 60 70 80 90 100 110 120 130 140 150
AMBIENT TEMPERATURE ( ^oC)
50
10
O₁
T
T₁
T₂
TIME
O₁ = Virtual Origin of Wave
T = Time From 10% to 90% of Peak
T₁ = Virtual Front Time = 1.25 • t
T₂ = Virtual Time to Half Value (Impulse Duration)
Example: For an 8/20µs Current Waveform:
8µs = T₁ = Virtual Front Time
20µs = T₂ = Virtual Time to Half Value
FIGURE 1. CURRENT, ENERGY AND POWER DERATING
CURVE
FIGURE 2. PEAK PULSE CURRENT TEST WAVEFORM
116
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