If you're looking for industry-leading varistor technology and other circuit protection devices you've come to the right place. Littelfuse circuit protection solutions are found virtually everywhere you look. Littelfuse offers a wide selection of overvoltage products to suppress transient voltages such as ESD (Electrostatic Discharge), automotive load dump, lightning, commutative spikes and other inductive transients. To learn more about varistor technology, including metal oxide varistors, surface mount multilayer varistors, and more, read on or follow this link: Varistor Technology.
A varistor is a voltage dependent, nonlinear device that has an electrical behavior similar to back-to-back Zener diodes. Varistors shunt transients away from circuits by presenting a low resistance path in the presence of overvoltage situations. They are the most broadly applied technology, protecting vulnerable circuit components in applications whether low or high energy and current ratings are required. Littelfuse varistor products are available with operating voltages from 2.5V to 2800VDC and 3.5-3500VDC. For more information about varistor technology, click here: Properties, Terminology & Theory (PDF). To find the right Littelfuse product for your project, follow this link: Varistor Applications.
The Littelfuse TMOV and iTMOV thermally protected varistor series represent a new development in integrated circuit protection. Both versions are comprised of radial leaded MOVs (Metal Oxide Varistors) with an integrated thermally activated element designed to open in the event of overheating due to the abnormal overvoltage, limited current, conditions outlined in UL 1449. The iTMOV varistor differs from the TMOV varistor by the inclusion of a third party lead for the purpose of indicating that the Metal Oxide Varistor has been disconnected from the circuit. This lead facilitates connection to monitoring circuitry. Additionally, TMOV and iTMOV varistor series are wave solderable, thus simplifying end product assembly by reducing the expense and rework associated with hand soldering operations.
Application Example | Typical Metal Oxide Varistor Series Selected |
TV / VCR / DVD / White Goods /Office Equipment | ZA, LA, UltraMOV®, TMOV®/iTMOV®, CIII, CH, MA, ML, MLE and MHS series |
Transformer (Primary Protection) | ZA, LA, UltraMOV®, TMOV®/iTMOV®, CIII, PA, HA, HB, NA, BA, BB, DA and DB series |
Instrumentation | |
Automotive (Primary/Secondary Protection) | |
Noise Suppression | |
Power Supply | PA, LA, UltraMOV®, CIII, ZA, HA, HB, NA, BA, BB, DA and DB series |
Transient Voltage Suppressor AC Power Strip | |
AC Distribution Panels | |
ESD Suppression |
A metal oxide varistor (MOV) is composed mainly of zinc oxide with small amounts of bismuth, manganese, cobalt, and other metal oxides. MOVs work by absorbing voltage surges and dissipating the energy as heat. Littelfuse metal oxide varistor products are available with peak current ratings ranging from 40A to 70,000A and peak energy ratings ranging from .1J to 10,000J. Littelfuse has the varistor you need regardless of the application. Available in radial leaded, axial leaded, surface mount, packaged and bare-disk options, Littelfuse MOVs are specifically designed to suppress transient voltages such as lightning and other high level transients found in industrial, AC line application or lower level transients found in automotive applications. The TMOV? and iTMOV? metal oxide varistor series include an integrated thermally activated element designed to open in the event of overheating due to sustained abnormal overvoltage, limited current, conditions outlined in UL1449.
Littelfuse multilayer varistor products are designed to protect a broad range of low voltage (0-120VDC) applications in the computer, handheld device, industrial and automotive markets. Littelfuse multilayer varistor products are manufactured from semi-conducting ceramics, and supplied in a leadless, surface mount package. All MLVs are RoHS compliant, 100% lead-free and compatible with modern reflow and wave soldering procedures.
Littelfuse multilayer varistor devices are designed to suppress a variety of transient events at the board level, including those specified in IEC 61000-4-2 or other standards used for Electromagnetic Compliance (EMC). The MLE and MHS series are designed to suppress ESD. The MHS is a low capacitance variation specifically designed to suppress ESD in high-speed (RS232 and USB 1.1) data lines. The ML series has a high energy capability and low clamping voltage, making it ideal for suppression of overvoltage transients such as inductive switching, EFT and repetitive ESD. With the exception of the MLN series, all of the multilayer varistor families are available in packages as small as 0402 size with a wide range of end-termination options including Nickel Barrier for improved solderability: Search Multilayer Varistor Products.
Littelfuse offers the broadest line of circuit protection products in the world. We deliver innovation, expertise, quality, and service. Please use the links on the left to explore circuit protection applications, products, and knowledgbase, or click here: Littelfuse Home.
Additional Information:
Metal Oxide Varistors
TVSS
Electrical Fuses
Fuse Holders
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