Varistor Metal Oxide Varistor Products Page 48 Varistor Metal-Oxide Varistor Products

2017 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 09/14/17 Metal-Oxide Varistors (MOVs) Surface Mount Multilayer Varistors (MLVs) > MLA Automotive Series Peak Current and Energy Derating Curve When 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 device. For applications exceeding 125C ambient temperature, the peak surge current and energy ratings must be derated as shown below. 100 80 60 40 20 0 -55 50 60 70 80 90 100 110 120 130 140 150 PERCENT OF RATED VALUE AMBIENT TEMPERATURE ( o C) T 1 T 2 100 50 0 O 1 TIME PERCENT OF PEAK VALUE T Peak Pulse Current Test Waveform for Clamping Voltage 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 s Current Waveform: 8 s = T 1 = Rise Time 20 s = T 2 = Decay Time Figure 1 Figure 2

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