Varistor Products
©2012 Littelfuse, Inc.
Revision: February 9, 2012
ZA Varistor Series
Radial Lead Varistors > ZA Series
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/za.html for current information.
Should transients occur in rapid succession, the average
power dissipation 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
Current Energy and Power Dissipation Ratings
Peak Pulse Current Test Waveform
100
90
50
10
O
1
T
T
1
T
2
TIME
PERCENT OF PEAK VALUE
0
1
7JSUVBM0SJHJOPG8BWF
55JNFGSPNUPPG1FBL
T
1
= Rise Time = 1.25 x T
T
2
= Decay Time
Example - For an 8/20 μT$VSSFOU8BWFGPSN
8μs = T
1
= Rise Time
20μs = T
2
= Decay Time
100
90
80
70
60
50
40
30
20
10
0
-55 50 60 70 80 90 100 110 120 130 140 150
AMBIENT TEMPERATURE (
o
C)
PERCENT OF RATED VALUE
Figure 1A - Power Derating for Epoxy Coated
Figure 2
100
90
80
70
60
50
40
30
20
10
0
-55 50 60 70 80 90 100 110 120 130 140 150
AMBIENT TEMPERATURE (
o
C)
PERCENT OF RATED VALUE
device. The operating values of a MOV need to be derated
at high temperatures as shown above. Because varistors
only dissipate a relatively small amount of average power
they are not suitable for repetitive applications that involve
substantial amounts of average power dissipation.
Figure 1B - Power Derating for Phenolic Coated
Phenolic Coating Option -- ZA Series Varistors for Hi-Temperature Operating Conditions:
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t 5IFTFEFWJDFTBMTPIBWFJNQSPWFEUFNQFSBUVSFDZDMJOHQFSGPSNBODFDBQBCJMJUZ
t 3BUJOHTBOETQFDJmDBUJPOTBSFBTQFSTUBOEBSE;"4FSJFTFYDFQU)Jo1PU
&ODBQTVMBUJPO*TPMBUJPO7PMUBHF$BQBCJMJUZ7
t 5PPSEFSBEEh9hUPQBSUOVNCFSFH7;"19
t 5IFTFEFWJDFTBSFOPU6-$4"7%&PS$&$$DFSUJmFE
t $POUBDUGBDUPSZGPSGVSUIFSEFUBJMT
t 1SPEVDUNBSLJOH
LF 9
P22P3
YYWW
Phenolic Coated
Option
Identifier
Lead-Free,
Halogen-Free
& RoHS Compliant
Indicator
