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<strong>Varistor</strong> <strong>Products</strong><br />
Line Voltage Operation, Radial Lead<br />
LA <strong>Varistor</strong> Series<br />
Device Ratings and Specifications (Continued)<br />
PART<br />
NUMBER<br />
MODEL<br />
SIZE<br />
DISC<br />
DIA.<br />
(mm)<br />
DEVICE<br />
MODEL<br />
NUMBER<br />
BRAND-<br />
ING<br />
V660LA10 10 660L 660 850 70 2500 940 1210 1820 25 70<br />
V660LA50A 14 660L50 660 850 140 4500 940 1210 1820 50 200<br />
V660LA100B 20 660L100 660 850 250 6500 940 1100 1650 100 400<br />
V1000LA80A 14 1000L80 1000 1200 220 4500 1425 1800 2700 50 130<br />
V1000LA160B 20 1000L160 1000 1200 360 6500 1425 1600 2420 100 250<br />
NOTE: Average power dissipation of transients not to exceed 0.25W, 0.4W, 0.6W or 1W for model sizes 7mm, 10mm, 14mm and 20mm, respectively.<br />
Power Dissipation Ratings<br />
Should transients occur in rapid succession, the average power dissipation<br />
is the energy (watt-seconds) per pulse times the number of pulses per<br />
second. The power so developed must be within the specifications shown<br />
on the Device Ratings and Specifications table for the specific device.The<br />
operating values of a MOV need to be derated at high temperatures as<br />
shown in Figure 1. Because varistors only dissipate a relatively small<br />
amount of average power they are not suitable for repetitive applications<br />
that involve substantial amounts of average power dissipation.<br />
PERCENT OF PEAK VALUE<br />
100<br />
O 1<br />
90<br />
50<br />
10<br />
T<br />
T1 T2 MAXIMUM RATING (85 oC) SPECIFICATIONS (25oC) CONTINUOUS TRANSIENT<br />
MAXIMUM TYPICAL<br />
PEAK VARISTOR VOLT- CLAMPING CAPACI-<br />
ENERGY CURRENT AGE AT 1mA DC VOLTAGE TANCE<br />
VRMS VDC 10 x 1000µs 8 x 20µs TEST CURRENT 8 x 20µs f = 1MHz<br />
VM(AC) VM(DC) WTM ITM VNOM MIN<br />
VNOM MAX VC IPK C<br />
(V) (V) (J) (A) (V) (V) (A) (pF)<br />
TIME<br />
FIGURE 2. PEAK PULSE CURRENT TEST WAVEFORM<br />
PERCENT OF RATED VALUE<br />
www.littelfuse.com<br />
100<br />
90<br />
80<br />
70<br />
60<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
-55 50 60 70 80 90 100 110 120 130 140 150<br />
AMBIENT TEMPERATURE ( oC) FIGURE 1. CURRENT, ENERGY AND POWER DERATING<br />
CURVE<br />
O 1 = Virtual Origin of Wave<br />
T = Time From 10% to 90% of Peak<br />
T 1 = Virtual Front time = 1.25 • t<br />
T 2 = Virtual Time to Half Value (Impulse Duration)<br />
Example: For an 8/20µs Current Waveform:<br />
8µs = T 1 = Virtual Front Time<br />
20µs = T 2 = Virtual Time to Half Value<br />
59<br />
2<br />
VARISTOR<br />
PRODUCTS
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