Varistor Metal Oxide Varistor Products Page 50 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 Device Characteristics At low current levels, the V-I curve of the multilayer transient voltage suppressor approaches a linear (ohmic) relationship and shows a temperature dependent effect. At or below the maximum working voltage, the suppressor is in a high resistance modex (approaching 10 6 at its maximum rated working voltage). Leakage currents at maximum rated voltage are below 100 A, typically 25 A. 100% 1E -9 1E -8 SUPPRESSOR CURRENT (A DC ) 10% 1E -7 1E -6 1E -5 1E -4 1E -3 1E -2 25 50 75 100 125 o C SUPPRESSOR VOLTAGE IN PERCENT OF V NOM VALUE AT 25 o C (%) o Clamping Voltage Over Temperature (V C at 10A) 100 10 20 V26MLA1206 40 60 80 100 120 140 TEMPERATURE ( o C) CLAMPING VOLTAGE (V) V5.5MLA1206 0 -20 -40 -60 Typical Temperature Dependance of the Haracteristic Curve in the Leakage Region Speed of Response The Multilayer Suppressor is a leadless device. Its response time is not limited by the parasitic lead inductances found in other surface mount packages. The response time of the Z N O dielectric material is less than 1ns and the MLA Automotive Series can clamp very fast dV/dT events such as ESD. Additionally, in "real world" applications, the associated circuit wiring is often the greatest factor effecting speed of response. Therefore, transient suppressor placement within a circuit can be considered important in certain instances. GRAINS DEPLETION FIRED CERAMIC DIELECTRIC REGION METAL ELECTRODES DEPLETION REGION METAL END TERMINATION Multilayer Internal Construction Energy Absorption/Peak Current Capability Energy dissipated within the MLA Automotive Series is calculated by multiplying the clamping voltage, transient current and transient duration. An important advantage of the multilayer is its interdigitated electrode construction within the mass of dielectric material. This results in excellent current distribution and the peak temperature per energy absorbed is very low. The matrix of semiconducting grains combine to absorb and distribute transient energy (heat) (see Speed of Response). This dramatically reduces peak temperature; thermal stresses and enhances device reliability. As a measure of the device capability in energy and peak current handling, the V26MLA1206 part was tested with multiple pulses at its peak current rating (150A, 8/20 s). At the end of the test,10,000 pulses later, the device voltage characteristics are still well within specification. 100 10 0 V26MLA1206 2000 4000 6000 8000 10000 12000 NUMBER OF PULSES VOLTAGE PEAK CURRENT = 3A 8/20 s DURATION, 30s BETWEEN PULSES Repetitive Pulse Capability Figure 8 Figure 9 Figure 10 Figure 11

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