Littelfuse DA_DB Varistor Series - Manual (Page 2)

© 2013 Littelfuse, Inc. 158
Revised: May 8, 2013
Varistor Products
DA/DB Varistor Series
Industrial High Energy Terminal Varistors > DA/DB Series
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/da or /db.html for current information.
Note : Average power dissipation of transients not to exceed 2.0W.
DA/DB Series Ratings & Specifications
Part Number
Device Branding
Maximum Rating (85ºC) Specifications (25ºC)
Continuous Transient
Varistor Voltage at 1mA
DC Test Current
Maximum
Clamping
Volt V
C
at
200A Current
(8/20μs)
Typical
Capaci-
tance f =
1MHz
V
RMS
V
DC
Energy
(2ms)
Peak
Current
8 x 20μs
V
M(AC)
V
M(DC)
W
TM
I
TM
Min V
NOM
Max V
C
C
DA DB (V) (V) (J) (A) (V) (V) (V) (A) (pF)
V131DA40 V131DB40 130 175 270 40000 1 184 200 228 345 10000
V151DA40 V151DB40 150 200 300 40000 2 212 240 268 405 8000
V251DA40 V251DB40 250 330 370 40000 354 390 429 650 5000
V271DA40 V271DB40 275 369 400 40000 389 430 473 730 4500
V321DA40 V321DB40 320 420 460 40000 462 510 561 830 3800
V421DA40 V421DB40 420 560 600 40000 610 680 748 1130 3000
V481DA40 V481DB40 480 640 650 40000 670 750 825 1240 2700
V511DA40 V511DB40 510 675 700 40000 735 820 910 1350 2500
V571DA40 V571DB40 575 730 770 40000 805 910 1000 1480 2200
V661DA40 V661DB40 660 850 900 40000 940 1050 1160 1720 2000
V751DA40 V751DB40 750 970 1050 40000 1080 1200 1320 2000 1800
Should transients occur in rapid succession, the
average power dissipation required is simply 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 above. Because varistors can only
dissipate a relatively small amount of average power they
are, therefore, not suitable for repetitive applications that
involve substantial amounts of average power dissipation.
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 15
PERCENT OF R
A
TED
V
ALUE
AMBIENT TEMPERATURE ( o C)
100
90
50
10
O 1 T
T 1
T 2
TIME
PERCENT OF PEAK V
ALUE
Peak Pulse Current Test Waveform
0
1
= Virtual Origin of Wave
T = Time from 10% to 90% of Peak
T
1
= Rise Time = 1.25 x T
T
2
= Decay Time
Example - For an 8/20 μs Current Waveform:
8μs = T
1
= Rise Time
20μs = T
2
= Decay Time
NOTES:
1. Peak current Applies to applications rated up to 115VRMS. Peak
current is 30kA for applications greater than 115V.
2. Peak current applies to applications rated up to 132VRMS. Peak
Current is 30kA for applications greater than 132V.
Figure 1
Figure 2