Mlv Design Guide Page 6 About The MLV Technology

About the MLV Technology The MLVs have a multilayer structure to absorb transient energy and maximize the effectiveness of the ZnO2 material of which they are made. Structure The MLVs are made of multiple fine-grain ceramic layers of a specific formulation. The MLV is constructed by forming a combination of alternating electrode plates and semiconducting ceramic layers into a block (Figure 8). Each layer of electrode is connected to the end termination on the opposite side. Figure 8. Cross-section View of Multilayer Suppressor Advantages of MLV Technology This interdigitated block formation greatly enhances the cross-sectional area available for active conduction of transients. This parallel arrangement of the inner electrode layers represents significantly more active surface area than the small outline of the package would suggest. This increased active surface area results in proportionally higher peak energy capability. Another advantage of this type of construction is that the breakdown voltage of the device is dependent on the dielectric thickness between the electrode layers, not the overall thickness of the device. Increasing or decreasing the dielectric thickness will change the breakdown voltage of the device. How Does a Multilayer Varistor Work? The crystalline structure of the MLV transient voltage suppressor consists of a matrix of fine, conductive grains separated by uniform grain boundaries, forming many P-N junctions (Figure 9). These boundaries are responsible for blocking conduction at low voltages, and are the source of the nonlinear electrical conduction at higher voltages. Conduction of the transient energy takes place between these P-N junctions. The uniform crystalline grains act as heat sinks for the energy absorbed by the device in a transient condition, and ensures an even distribution of the transient energy (heat) throughout the device. This even distribution results in enhanced transient energy capability and long-term reliability. Figure 9. Crystalline Structure of Multilayer Suppressor With MLV technology, energy-handling capability can be significantly increased with a larger overall package outline. The energy-handling capability doubles from 0.6J (10/1000 s waveform) for a 0.120-inch by 0.06-inch device (1206) to 1.2J for a 0.120-inch by 0.100-inch (1210) device. As a result, MLVs are well-suited for the increasing demand for ESD protection for handheld and wearable devices. As the result of extensive research, Littelfuse can now offer the industry a 0201-size MLV. Inner Electrodes End Termination Semiconducting Ceramic GRAINS DEPLETION FIRED CERAMIC DIELECTRIC REGION METAL ELECTR ODES DEPLETION REGION METAL END TERMINATION Surface Mount Multilayer Varistors (MLVs) Design Guide 2016 Littelfuse Multilayer Varistors (MLVs) Design Guide About the MLV Technology 6

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