Product Specific Application Notes
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The files below are downloadable versions of product specific "Application Notes", i.e. they refer to the specific properties or application of a specific series or technology of Littelfuse or Teccor® brand devices.
The files below are downloadable versions of product specific "Application Notes", i.e. they refer to the specific properties or application of a specific series or technology of Littelfuse or Teccor® brand devices.
AN9773 - Varistor Testing
This application note details the common tests of varistor parameters and describes suitable test methods using simplified test circuits. All tests are performed at 25° C, unless otherwise specified. The test circuits and methods given are intended as a general guide. Since the tests frequently entail high voltages and currents, users must exercise appropriate safety precautions.
AN9311 - The ABCs of MOVs
The material in this application guide has been arranged in 3 parts for easy reference; Section A provides general guidelines on what types of MOV products are best suited for particular environments. Section B explains what Metal Oxide Varistors are and the basic function they perform. And section C helps clarify important information about MOVs for the design engineer, and answers questions that are asked most often.
AN9671 - The ABCs of Littelfuse Multilayer Suppressors
This application 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. Applications are covered, giving general examples of where these products are used. The Basics, describes the fundamental fabrication, operation and functions. And Common Questions addresses frequently asked questions from Production Engineers, and Designers.
AN1007 - Teccor® Thyristors Used as AC Static Switches and Relays
This application note describes circuits in which these thyristors are used to perform simple switching functions of a general type that might also be performed non-statically by various mechanical and electromechanical switches. In these applications, the thyristors are used to open or close a circuit completely, as opposed to applications in which they are used to control the magnitude of average voltage or energy being delivered to a load. These latter types of applications are described in detail in "Phase Control Using Thyristors"(AN1003).
AN9708 - SP720, SP721 and SP723 Turn-On and Turn-Off Characteristics
The purpose of this application note is to focus on customer concerns related to the fast switching characteristics of the SP720, SP721 and SP723 family of protection ICs during an ESD discharge. The SCR cell structures of this family were first introduced for ESD protection of sensitive ICs that were subject to substantially more severe conditions than normal Human Body Model stress.
EC623A - Selecting an ESD Suppressor
This selection guide is an aid to the decision-making process. It provides information for considering the use of ESD suppressors and discusses the relative issues.
AN9767 - Littelfuse Varistors: Basic Properties, Terminology and Theory
This application note describes the basic properties of varistors. Varistors are voltage dependent, nonlinear devices which have an electrical behavior similar to back-to-back zener diodes. The symmetrical, sharp breakdown characteristics enable the varistor to provide excellent transient suppression performance.
EC638 - Littelfuse Varistor Design Examples
This application note is a guide for selecting a varistor by describing common application examples, and illustrating the solution process to determine the appropriate varistor. The note also describes series/parallel connection rules.
AN9108 - Littelfuse "ML" Multilayer Surface Mount Surge Suppressors
This application note focuses on the ML version multilayer suppressor. Littelfuse produces four families of multilayer suppressor, including the ML, MLE, MLN and AUML. Much of the information presented here is generic to all four.
AN9108 - Littelfuse "ML" Multilayer Surface Mount Surge Suppressors
This application note focuses on the ML version multilayer suppressor. Littelfuse produces four families of multilayer suppressor, including the ML, MLE, MLN and AUML. Much of the information presented here is generic to all four.
EC635 - Designing with thermally protected TMOV Varistors in TVSS Applications
This application note discusses the methods that exist to prevent MOVs from reaching combustible temperatures and focuses on the new integrated TMOV varistor thermal fuse technology which reduces part count, saves space and is UL1449 recognized.
AN1010 - Teccor® Thyristors for Ignition of Fluorescent Lamps
One of the many applications for Teccor thyristors is in fluorescent lighting. Standard conventional and circular fluorescent lamps with filaments can be ignited easily and much more quickly by using thyristors instead of the mechanical starter switch, and solid state thyristors are more reliable. Thyristors produce a pure solid state igniting circuit with no mechanical parts in the fluorescent lamp fixture. Also, because the lamp ignites much faster, the life of the fluorescent lamp can be increased since the filaments are activated for less time during the ignition. The thyristor ignition eliminates any audible noise or flashing off and on which most mechanical starters possess.
AN1009 - Teccor® Thyristors - Miscellaneous Design Tips and Facts
This application note presents design tips and facts on the following
topics:
-Relationship of IAV, IRMS, and IPK
-dv/dt Definitions
-Examples of gate terminations
-Curves for Average Current at Various Conduction Angles
-Double-exponential Impulse Waveform
-Failure Modes of Thyristor
-Characteristics Formulas for Phase Control
AN1008 - Explanation of Maximum Ratings and Characteristics for Thyristors
Data sheets for SCRs and triacs give vital information regarding maximum ratings and characteristics of thyristors. If the maximum ratings of the thyristors are surpassed, possible irreversible damage may occur. This application note explains those ratings and describe various pertinent device parameters which are guaranteed as either minimums or maximums.
AN1006 - Testing Teccor® Semiconductor Devices Using Curve Tracers
One of the most useful and versatile instruments for testing semiconductor devices is the curve tracer (CT). Although widely used by semiconductor
manufacturers for design and analytical work, the device consumer will find many uses for the curve tracer, such as incoming quality control, failure analysis, and supplier comparison. Curve tracers may be easily adapted for go-no go production testing. This application note describes how to use curve tracers.
AN1005 - Teccor® Thyristor Surface Mount Soldering Recommendations
The most important consideration in reliability is achieving a good solder bond between surface mount device (SMD) and substrate since the solder provides the thermal path from the chip. A good bond is less subject to thermal fatiguing and will result in improved device reliability. This application note discusses the different soldering methods for Littelfuse's Teccor brand thyristor products.
AN1004 - Mounting and Handling of Semiconductor Devices
Proper mounting and handling of semiconductor devices, particularly those used in power applications, is an important, yet sometimes overlooked, consideration in the assembly of electronic systems. Power devices need adequate heat dissipation to increase operating life and reliability and allow the device to operate within manufacturers' specifications. Also, in order to avoid damage to the semiconductor chip or internal assembly, the devices should not be abused during assembly. Very often, device failures can be attributed directly to a heat sinking or assembly damage problem. The information in this application note guides the semiconductor user in the proper use of Teccor devices, particularly the popular and versatile TO-220 and TO-202 epoxy packages.
AN1003 - Phase Control Using Teccor® Thyristors
Due to high-volume production techniques, thyristors are now priced so that almost any electrical product can benefit from electronic control. A look at the fundamentals of SCR and triac phase controls shows how this is possible.
AN1002 - Gating, Latching, and Holding of SCRs and Triacs
Gating, latching, and holding currents of thyristors are some of the most important parameters. These parameters and their interrelationship determine whether the SCRs and triacs will function properly in various circuit applications.
This application note describes how the SCR and triac parameters are related. This knowledge helps users select best operating modes for various circuit applications.
AN1001 - Fundamental Characteristics of Thyristors
The thyristor family of semiconductors consists of several very useful devices. The most widely used of this family are silicon controlled rectifiers (SCRs), triacs, sidacs, and diacs. In many applications these devices perform key functions and are real assets in meeting environmental, speed, and reliability specifications which their electro-mechanical counterparts cannot fulfill.
This application note presents the basic fundamentals of SCR, triac, sidac, and diac thyristors so the user understands how they differ in characteristics and parameters from their electromechanical counterparts. Also, thyristor terminology is defined.
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