Littelfuse ATMOV Varistor Series - Manual (Page 3)

Varistor Products
© 2014 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 02/18/14
3
Radial Leaded Varistors > ATMOV Series
LV UltraMO
V ™
S
eries
Current Energy and Power Dissipation Ratings
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 ( o C)
PERCENT OF
RA
TED
VALUE
Figure 1A - Power Derating for Epoxy Coated
FIGURE 1. CURRENT, ENERGY AND POWER DERATING
CURVE
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 ( o C)
PERCENT OF
RA
TED
VALUE
Figure 1B - Power Derating for Phenolic Coated
t 1
t 2
100
50
0
O 1
TIME
PERCENT OF PEAK
VALUE
t
Peak Pulse Current Test Waveform for Clamping Voltage
0
1
= Virtual Origin of Wave
t = Time from 10% to 90% of Peak
t
1
= Virtual Front Time = 1.25 x t
t
2
= Virtual Time to Half-Value (Impulse Duration)
Example - For an 8/20 µs Current Waveform:
8µs = t
1
= Virtual Front Time
20µs = t
2
= Virtual Time to Half-Value
Figure 2: Peak Pulse Current Test Waveform for Clamping Voltage
For applications exceeding 85ºC ambient temperature,
the peak surge current and energy ratings must be
reduced as shown below. For applications exceeding 125ºC ambient temperature,
the peak surge current and energy ratings must be
reduced as shown below.