V18ZA05 Datasheet, PDF (5/12 Pages) Harris Corporation – Radial Lead Metal-Oxide Varistors for Low to Medium Voltage Operation

ZA Series
Power Dissipation Ratings
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 in Figure 1.
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.
1.
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 (^oC)
FIGURE 1. CURRENT, ENERGY AND POWER DERATING
CURVE
100
90
50
10
O₁
T
T₁
T₂
TIME
O₁ = Virtual Origin of Wave
T = Time From 10% to 90% of Peak
T₁ = Virtual Front time = 1.25 • t
T₂ = Virtual Time to Half Value (Impulse Duration)
Example: For an 8/20µs Current Waveform:
8µs = T₁ = Virtual Front Time
20µs = T₂ = Virtual Time to Half Value
FIGURE 2. PEAK PULSE CURRENT TEST WAVEFORM
Transient V-I Characteristics Curves
600
500
MAX CLAMPING VOLTAGE
MODEL SIZE 5mm
400
300
8 TO
T_A =
-6585V^oNC^(DT^CO⁾
RATING
85^oC
200
100
90
80
70
60
V68ZA05
V56ZA05
V47ZA05
50 V39ZA05
40
V33ZA05
V27ZA05
30
V22ZA05
V18ZA05
20 ^V12ZA05
V8ZA05
10
10^-3
10^-2
10^-1
10⁰
10¹
10²
10³
PEAK AMPERES (A)
FIGURE 3. CLAMPING VOLTAGE FOR V8ZA05 - V68ZA05
2000
1000
500
V330ZA05
V270ZA05
V240ZA05
V220ZA05
V205ZA05
V180ZA05
V150ZA05
V120ZA05
MAX CLAMPING VOLTAGE
MODEL SIZE 5mm
82
T_A
T=O-5353_o0CVT_{NO(D8C5) o}RCATING
200
V1V0802ZZAA0055
100
0.0001 0.001
0.01
0.1
1
10
PEAK AMPERES (A)
100 1000
FIGURE 4. CLAMPING VOLTAGE FOR V82ZA05 - V330ZA05
4-38