Datasheet V275LA4P (Littelfuse) - 4

Metal-Oxide Varistors
(MOVs) Radial Lead Varistors > LA Varistor Series
Copper Electrode Option:
• Add 'W' to the end of the part number (e.g. V230LA20AP
W
) • Product marking: LF 9 P230L20W Lead-Free, YYWW Copper Electrode Halogen-Free Option & RoHS Compliant Identifier Indicator
Current Energy and Power Dissipation Ratings
Should transients occur in rapid succession, the average device. The operating values of a MOV need to be derated power dissipation is the energy (watt-seconds) per pulse at high temperatures as shown above. Because varistors times the number of pulses per second. The power so only dissipate a relatively small amount of average power developed must be within the specifications shown on the they are not suitable for repetitive applications that involve Device Ratings and Specifications Table for the specific substantial amounts of average power dissipation.
Figure 1A - Power Derating for Epoxy Coated Figure 1B - Power Derating for Phenolic Coated 100
100
90
90
80
80
VALUE alue 70
70
TED 60
60
RA 50
50 40
40
30
30
20
PERCENT OF 20 Percentage of Rated V
10
10
0
0
-55 50 60 70 80 90 100 110 120 130 140 150
-55 50 60 70 80 90 100 110 120 130 140 150 AMBIENT TEMPERATURE ( oC) Ambient Temperature (ºC) FIGURE 1. CURRENT, ENERGY AND POWER DERATING Peak Pulse Current CURVETest Waveform 100 VALUE
0 = Virtual Origin of Wave
90
1 T = Time from 10% to 90% of Peak T = Rise Time = 1.25 x T 1
50
T = Decay Time 2
Example
- For an 8/20 µs Current Waveform: 8µs = T = Rise Time 1 20 = Decay Time
PERCENT OF PEAK
µs = T2
10 O 1 T TIME T1 Figure 2 T2
O 1 = Virtual Origin of Wave T = Time From 10% to 90% of Peak T 1 = Virtual Front time = 1.25 • t T 2 = Virtual Time to Half Value (Impulse Duration) Example: For an 8/20 µs Current Waveform: 8 s = T 1 = Virtual Front Time 20 s = T 2 = Virtual Time to Half Value
FIGURE 2. PEAK PULSE CURRENT TEST WAVEFORM
© 2019 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 12/17/19