From Littelfuse, Inc.
Littelfuse offers three device technologies for the suppression of ESD events and other EMC-related transients. These are the MultiLayer Metal Oxide Varistor, silicon (SCR/Diode Array and TVS Avalanche Diode Arrays) and Polymeric Voltage Variable Material technologies. Though these products have different characteristics, they have the common goal of protecting sensitive components from transients that threaten their survivability and functionality. Additionally, EMC legislation, or other immunity requirements, may mean that existing products require suppression devices in order to be compliant with the applicable immunity test.
As with all decision-making processes, information is the key when considering the use of ESD suppressors. It is critical that the circuit characteristics are defined. For example, the capacitance value of the ESD suppressor will limit its usage on communication lines. As the speed of the data increases, the capacitance (if it is too large) can distort or attenuate the data. Ideally, the Design Engineer will gather basic circuit information such as data rate, allowable leakage current, line voltage, size constraints, and number of lines that require protection. This information can then be used to compare the circuit conditions to the ESD suppressor characteristics to find the best "match". To help with the "matching" process, a suppressor characteristic table is included below, and a selection flowchart can be found on the next page.
Products & Services
Fuses protect electrical devices and components from overcurrents and short circuits that occur in improperly operating circuits.
Load centers are used for the protection and distribution of power in a building or residence. They are also called circuit breaker boxes.
Circuit breakers are mechanical switching devices capable of breaking currents under specified abnormal circuit conditions.
Ground Fault Relays
Ground fault relays protect electrical equipment from ground faults. A ground fault is an unintentional current path between a current-carrying conductor and a grounded surface.
Fuse holders are devices for containing, protecting and mounting fuses. Blown fuses can be changed quickly and easily when used in conjunction with a fuse holder.
Topics of Interest
In previous Technical Briefs, it was introduced that Littelfuse offers a family of ESD suppression technologies including ceramic MultiLayer Varistors (MLV's), silicon (SP72x SCR/Diode and SP05xx TVS...
This guide is similar to "The ABCs of MOVs", offering specific information on Multilayer suppressor device technology and is intended to be a supplement to the Littelfuse Multilayer data sheets.
This note is meant to be a guide for the user in selecting a varistor by describing common application examples, and illustrating the solution process to determine the appropriate varisor. The note...
The Transient Voltage Suppressor diode (T.V.S.) is specifically designed to protect electronic circuits against transients and over voltages. It is a silicon avalanche device available in both...
Silicon avalanche diode based SPDs (surge protection devices) are increasingly being recommended to protect expensive and sensitive electronic equipment from lightning and surges. This is due to their...