Application Notes

Below is a list of application notes organized by segment.

 
 Automotive
AN612 - IEC 61000-4-2 ESD Immunity and Transient Current Capability for the SP72X Series Protection Arrays
an9612.pdf (120,435 bytes)
This application note covers IEC 61000-4-2 ESD immunity and transient current capability for the SP72X Series protection arrays. The SP720, SP721, SP723, and SP724 are protection ICs with an array of SCR/Diode bipolar structures for ESD and over-voltage protection of sensitive input circuits. They have 2 protection SCR/Diode device structures per input.
 
AN9108 - Littelfuse "ML" Multilayer Surface Mount Surge Suppressors
an9108.pdf (151,570 bytes)
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.
 
AN9304 - ESD and Transient Protection Using the SP720
an9304.pdf (235,590 bytes)
This application note discusses ESD and transient protection using the SP720. For a given level of voltage or power, there is a defined degree of protection compatible to that need. For the SP720, the protection circuits are designed to clamp over-voltage within a range of peak current that will substantially improve the survival input expectancy of average monolithic silicon circuits used for small signal and digital processing applications.
 
AN9311 - The ABCs of MOVs
an9311.pdf (68,967 bytes)
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.
 
AN9312 - Suppression of Transients in an Automotive Environment
an9312.pdf (176,962 bytes)
This application note discusses suppression of transients in the automotive environment. The circuit designer must ensure reliable circuit operation in this severe transient environment. The transients on the automobile power supply range from the severe, high energy, transients generated by the alternator/regulator system to the low-level "noise" generated by the ignition system and various accessories.
 
AN9671 - The ABCs of Littelfuse Multilayer Suppressors
an9671.pdf (61,336 bytes)
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.
 
AN9767 - Littelfuse Varistors: Basic Properties, Terminology and Theory
Littelfuse_app-note_an9767.pdf (1,120,557 bytes)
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.
 
AN9768 - Transient Suppression Devices and Principles
an9768.pdf (128,962 bytes)
This application note discusses the two major categories of transient suppressors: a) those that attenuate transients, thus preventing their propagation into the sensitive circuit; and b) those that divert transients away from sensitive loads and so limit the residual voltages.
 
EC621A - The ESD Problem
ec621a.pdf (173,377 bytes)
This technical brief defines Electrostatic Discharge(ESD), provides examples and discusses the issues surrounding protection against it.
 
EC622A - ESD Suppression Technologies
ec622a.pdf (176,397 bytes)
This technical brief discusses the three distinct Littelfuse product families that can be used for ESD suppression. These include the electroceramic MLV (MultiLayer Varistor), silicon (SP72x and SP050x) and polymer-based PulseGuard™ suppressor products.
 
EC623A - Selecting an ESD Suppressor
ec623a.pdf (149,769 bytes)
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.
 
EC624 - Capacitance and Signal Integrity
ec624.pdf (182,782 bytes)
This technical brief includes an introduction to capacitance to show that the capacitance characteristic is an important criterion when choosing an ESD suppressor. The effectiveness of ESD suppression technologies is not questioned here, rather it is noted that signal integrity can be compromised if capacitance is not taken into account.
 
EC625 - ESD Protection Audio Input and Output Lines
ec625.pdf (170,580 bytes)
The purpose of this application brief is to detail audio port protection and discuss how these ports are sensitive to both external and internal sources of overvoltage transients in the form of external electro-static Discharge (ESD) or internally generated electrical fast transients (EFT).
 
EC628 - ESD Protection IEEE 1394 Data Lines
ec628.pdf (227,858 bytes)
This technical brief discusses how IEEE 1394 products (PCI adapter cards, hubs/routers, etc.) can be susceptible to ESD events when the cable is disconnected from the data port and how the integrated circuitry that controls the IEEE 1394 functionality can be compromised.
 
EC634 - General Purpose ESD Protection
ec634.pdf (137,763 bytes)
The purpose of this application brief is to detail (General Purpose) transient protection with signal bandwidth less than 125 Mbps and discusses how electronic systems are sensitive to both external and internal sources of overvoltage transients in the form of external Electro-Static Discharge (ESD) or internally generated Electrical Fast Transients (EFT).
 
EC638 - Littelfuse Varistor Design Examples
EC638.pdf (365,425 bytes)
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.
 
 Digital Consumer Electronics
AN1001 - Fundamental Characteristics of Thyristors
AN1001.pdf (125,085 bytes)
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.
 
AN1002 - Gating, Latching, and Holding of SCRs and Triacs
AN1002.pdf (107,122 bytes)
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.
 
AN1003 - Phase Control Using Teccor® Thyristors
AN1003.pdf (172,663 bytes)
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.
 
AN1004 - Mounting and Handling of Semiconductor Devices
AN1004.pdf (153,554 bytes)
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.
 
AN1005 - Teccor® Thyristor Surface Mount Soldering Recommendations
AN1005.pdf (173,766 bytes)
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.
 
AN1006 - Testing Teccor® Semiconductor Devices Using Curve Tracers
AN1006.pdf (318,021 bytes)
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.
 
AN1007 - Teccor® Thyristors Used as AC Static Switches and Relays
AN1007.pdf (186,953 bytes)
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).
 
AN1009 - Teccor® Thyristors - Miscellaneous Design Tips and Facts
AN1009.pdf (111,513 bytes)
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
 
AN612 - IEC 61000-4-2 ESD Immunity and Transient Current Capability for the SP72X Series Protection Arrays
an9612.pdf (120,435 bytes)
This application note covers IEC 61000-4-2 ESD immunity and transient current capability for the SP72X Series protection arrays. The SP720, SP721, SP723, and SP724 are protection ICs with an array of SCR/Diode bipolar structures for ESD and over-voltage protection of sensitive input circuits. They have 2 protection SCR/Diode device structures per input.
 
AN9108 - Littelfuse "ML" Multilayer Surface Mount Surge Suppressors
an9108.pdf (151,570 bytes)
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.
 
AN9211 - Soldering Recommendations for Surface Mount and Multilayer Metal Oxide Varistors
an9211.pdf (98,771 bytes)
This application note discusses recommendations for soldering surfacemount. MMOVcomponents. Surface mount technology has the advantages of lower costs, increased reliability and the reduction in the size and weight of components used. With these advantages, surface mount technology is fast becoming the norm in circuit design.
 
AN9304 - ESD and Transient Protection Using the SP720
an9304.pdf (235,590 bytes)
This application note discusses ESD and transient protection using the SP720. For a given level of voltage or power, there is a defined degree of protection compatible to that need. For the SP720, the protection circuits are designed to clamp over-voltage within a range of peak current that will substantially improve the survival input expectancy of average monolithic silicon circuits used for small signal and digital processing applications.
 
AN9311 - The ABCs of MOVs
an9311.pdf (68,967 bytes)
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
an9671.pdf (61,336 bytes)
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.
 
AN9708 - SP720, SP721 and SP723 Turn-On and Turn-Off Characteristics
an9708.pdf (99,012 bytes)
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.
 
AN9734 - IEC Electromagnetic Compatibility Standards for Industrial Process Measurement and Control Equipment
an9734.pdf (521,292 bytes)
This application note discusses the purpose of the International Electrotechnical Commission lEC 61000-4 (previously known as lEC-801) standard which established a common reference for evaluating the performance of industrial-process measurement and control instrumentation when exposed to electric or electromagnetic interference.
 
AN9767 - Littelfuse Varistors: Basic Properties, Terminology and Theory
Littelfuse_app-note_an9767.pdf (1,120,557 bytes)
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.
 
AN9768 - Transient Suppression Devices and Principles
an9768.pdf (128,962 bytes)
This application note discusses the two major categories of transient suppressors: a) those that attenuate transients, thus preventing their propagation into the sensitive circuit; and b) those that divert transients away from sensitive loads and so limit the residual voltages.
 
AN9769 - An Overview of Electromagnetic and Lightning Induced Voltage Transients
an9769.pdf (184,609 bytes)
This application note is an overview of the sources and nature of various transient overvoltages, and the problems that may result.
 
AN9773 - Varistor Testing
an9773.pdf (281,334 bytes)
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.
 
CATV Equipment Protection
5CATV.pdf (112,151 bytes)
As cable providers enter the local exchange market, protection of CATV (Community Antenna TV) equipment becomes even more critical in order to ensure reliable operation of equipment and uninterrupted service.
 
Data Line Protectors
9DataLine.pdf (96,822 bytes)
In many office and industrial locations, data lines (such as RS-232 and ethernet) and AC power lines run in close proximity to each other, which often results in voltage spikes being induced onto the data line, causing damage to sensitive equipment.
 
EC606 - Protecting the Universal Serial Bus from Over Voltage and Overcurrent Threats
ec606.pdf (117,212 bytes)
This application note addresses the various requirements for protecting the Universal Serial Bus (USB) from overcurrent and over voltage environmental threats.The solutions presented cover both USB 1.1 and the higher speed USB 2.0 circuitry.
 
EC616 - Circuit Protection of USB 2.0
ec616.pdf (493,693 bytes)
This application brief demonstrates how to ensure reliable and safe circuit operation of USB products, protection against voltage and current transients must be carefully considered. Due to the higher data rates of USB 2.0, attention to the electrical characteristics of protection solutions is required.
 
EC621A - The ESD Problem
ec621a.pdf (173,377 bytes)
This technical brief defines Electrostatic Discharge(ESD), provides examples and discusses the issues surrounding protection against it.
 
EC622A - ESD Suppression Technologies
ec622a.pdf (176,397 bytes)
This technical brief discusses the three distinct Littelfuse product families that can be used for ESD suppression. These include the electroceramic MLV (MultiLayer Varistor), silicon (SP72x and SP050x) and polymer-based PulseGuard™ suppressor products.
 
EC623A - Selecting an ESD Suppressor
ec623a.pdf (149,769 bytes)
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.
 
EC624 - Capacitance and Signal Integrity
ec624.pdf (182,782 bytes)
This technical brief includes an introduction to capacitance to show that the capacitance characteristic is an important criterion when choosing an ESD suppressor. The effectiveness of ESD suppression technologies is not questioned here, rather it is noted that signal integrity can be compromised if capacitance is not taken into account.
 
EC625 - ESD Protection Audio Input and Output Lines
ec625.pdf (170,580 bytes)
The purpose of this application brief is to detail audio port protection and discuss how these ports are sensitive to both external and internal sources of overvoltage transients in the form of external electro-static Discharge (ESD) or internally generated electrical fast transients (EFT).
 
EC627 - ESD Protection Digital Visual Interface Data Lines
ec627.pdf (191,662 bytes)
This technical brief covers the Digital Visual Interface (DVI) products (source and display units) how how then can become susceptible to ESD events when the cable is disconnected from the data port and how the integrated circuitry that controls the DVI system functionality can be compromised.
 
EC628 - ESD Protection IEEE 1394 Data Lines
ec628.pdf (227,858 bytes)
This technical brief discusses how IEEE 1394 products (PCI adapter cards, hubs/routers, etc.) can be susceptible to ESD events when the cable is disconnected from the data port and how the integrated circuitry that controls the IEEE 1394 functionality can be compromised.
 
EC630 - ESD Protection USB 1.1 Data Lines
ec630.pdf (159,300 bytes)
This technical brief covers how Universal Serial Bus (USB) products (PCI adapter cards, digital cameras, peripherals, etc.) can be susceptible to ESD events when the cable is disconnected from the data port. The ESD pulse can be introduced directly into the open port, or into the disconnected end of the cable and the integrated circuitry that controls the USB functionality can be compromised.
 
EC631 - ESD Protection USB 2.0 Data Lines
ec631.pdf (221,196 bytes)
This technical brief covers how Universal Serial Bus (USB) 2.0 products (PCI adapter cards, digital cameras, peripherals, etc.) can be susceptible to ESD events when the cable is disconnected from the data port. The ESD pulse can be introduced directly into the open port, or into the disconnected end of the cable and the integrated circuitry that controls the USB functionality can be compromised.
 
EC634 - General Purpose ESD Protection
ec634.pdf (137,763 bytes)
The purpose of this application brief is to detail (General Purpose) transient protection with signal bandwidth less than 125 Mbps and discusses how electronic systems are sensitive to both external and internal sources of overvoltage transients in the form of external Electro-Static Discharge (ESD) or internally generated Electrical Fast Transients (EFT).
 
EC638 - Littelfuse Varistor Design Examples
EC638.pdf (365,425 bytes)
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.
 
Triggering and Gate Characteristics of Thyristors
01_trigg.pdf (3,273,341 bytes)
 
 Electrical/Industrial Electronics
AN1001 - Fundamental Characteristics of Thyristors
AN1001.pdf (125,085 bytes)
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.
 
AN1002 - Gating, Latching, and Holding of SCRs and Triacs
AN1002.pdf (107,122 bytes)
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.
 
AN1003 - Phase Control Using Teccor® Thyristors
AN1003.pdf (172,663 bytes)
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.
 
AN1004 - Mounting and Handling of Semiconductor Devices
AN1004.pdf (153,554 bytes)
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.
 
AN1005 - Teccor® Thyristor Surface Mount Soldering Recommendations
AN1005.pdf (173,766 bytes)
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.
 
AN1006 - Testing Teccor® Semiconductor Devices Using Curve Tracers
AN1006.pdf (318,021 bytes)
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.
 
AN1007 - Teccor® Thyristors Used as AC Static Switches and Relays
AN1007.pdf (186,953 bytes)
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).
 
AN1008 - Explanation of Maximum Ratings and Characteristics for Thyristors
AN1008.pdf (126,437 bytes)
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.
 
AN1009 - Teccor® Thyristors - Miscellaneous Design Tips and Facts
AN1009.pdf (111,513 bytes)
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
 
AN1010 - Teccor® Thyristors for Ignition of Fluorescent Lamps
AN1010.pdf (86,399 bytes)
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.
 
AN612 - IEC 61000-4-2 ESD Immunity and Transient Current Capability for the SP72X Series Protection Arrays
an9612.pdf (120,435 bytes)
This application note covers IEC 61000-4-2 ESD immunity and transient current capability for the SP72X Series protection arrays. The SP720, SP721, SP723, and SP724 are protection ICs with an array of SCR/Diode bipolar structures for ESD and over-voltage protection of sensitive input circuits. They have 2 protection SCR/Diode device structures per input.
 
AN9108 - Littelfuse "ML" Multilayer Surface Mount Surge Suppressors
an9108.pdf (151,570 bytes)
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.
 
AN9211 - Soldering Recommendations for Surface Mount and Multilayer Metal Oxide Varistors
an9211.pdf (98,771 bytes)
This application note discusses recommendations for soldering surfacemount. MMOVcomponents. Surface mount technology has the advantages of lower costs, increased reliability and the reduction in the size and weight of components used. With these advantages, surface mount technology is fast becoming the norm in circuit design.
 
AN9311 - The ABCs of MOVs
an9311.pdf (68,967 bytes)
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
an9671.pdf (61,336 bytes)
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.
 
AN9708 - SP720, SP721 and SP723 Turn-On and Turn-Off Characteristics
an9708.pdf (99,012 bytes)
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.
 
AN9734 - IEC Electromagnetic Compatibility Standards for Industrial Process Measurement and Control Equipment
an9734.pdf (521,292 bytes)
This application note discusses the purpose of the International Electrotechnical Commission lEC 61000-4 (previously known as lEC-801) standard which established a common reference for evaluating the performance of industrial-process measurement and control instrumentation when exposed to electric or electromagnetic interference.
 
AN9767 - Littelfuse Varistors: Basic Properties, Terminology and Theory
Littelfuse_app-note_an9767.pdf (1,120,557 bytes)
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.
 
AN9768 - Transient Suppression Devices and Principles
an9768.pdf (128,962 bytes)
This application note discusses the two major categories of transient suppressors: a) those that attenuate transients, thus preventing their propagation into the sensitive circuit; and b) those that divert transients away from sensitive loads and so limit the residual voltages.
 
AN9769 - An Overview of Electromagnetic and Lightning Induced Voltage Transients
an9769.pdf (184,609 bytes)
This application note is an overview of the sources and nature of various transient overvoltages, and the problems that may result.
 
AN9773 - Varistor Testing
an9773.pdf (281,334 bytes)
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.
 
Data Line Protectors
9DataLine.pdf (96,822 bytes)
In many office and industrial locations, data lines (such as RS-232 and ethernet) and AC power lines run in close proximity to each other, which often results in voltage spikes being induced onto the data line, causing damage to sensitive equipment.
 
EC606 - Protecting the Universal Serial Bus from Over Voltage and Overcurrent Threats
ec606.pdf (117,212 bytes)
This application note addresses the various requirements for protecting the Universal Serial Bus (USB) from overcurrent and over voltage environmental threats.The solutions presented cover both USB 1.1 and the higher speed USB 2.0 circuitry.
 
EC608 - Considerations for Selecting Littelfuse MOVs and Fuses for Industrial Motor Applications
ec608.pdf (176,090 bytes)
This application note discusses the first level considerations for applying both Littelfuse Industrial AC Line Metal Oxide Varistors and associated AC line Fuses with a motor protection example.
 
EC621A - The ESD Problem
ec621a.pdf (173,377 bytes)
This technical brief defines Electrostatic Discharge(ESD), provides examples and discusses the issues surrounding protection against it.
 
EC622A - ESD Suppression Technologies
ec622a.pdf (176,397 bytes)
This technical brief discusses the three distinct Littelfuse product families that can be used for ESD suppression. These include the electroceramic MLV (MultiLayer Varistor), silicon (SP72x and SP050x) and polymer-based PulseGuard™ suppressor products.
 
EC623A - Selecting an ESD Suppressor
ec623a.pdf (149,769 bytes)
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.
 
EC624 - Capacitance and Signal Integrity
ec624.pdf (182,782 bytes)
This technical brief includes an introduction to capacitance to show that the capacitance characteristic is an important criterion when choosing an ESD suppressor. The effectiveness of ESD suppression technologies is not questioned here, rather it is noted that signal integrity can be compromised if capacitance is not taken into account.
 
EC628 - ESD Protection IEEE 1394 Data Lines
ec628.pdf (227,858 bytes)
This technical brief discusses how IEEE 1394 products (PCI adapter cards, hubs/routers, etc.) can be susceptible to ESD events when the cable is disconnected from the data port and how the integrated circuitry that controls the IEEE 1394 functionality can be compromised.
 
EC630 - ESD Protection USB 1.1 Data Lines
ec630.pdf (159,300 bytes)
This technical brief covers how Universal Serial Bus (USB) products (PCI adapter cards, digital cameras, peripherals, etc.) can be susceptible to ESD events when the cable is disconnected from the data port. The ESD pulse can be introduced directly into the open port, or into the disconnected end of the cable and the integrated circuitry that controls the USB functionality can be compromised.
 
EC631 - ESD Protection USB 2.0 Data Lines
ec631.pdf (221,196 bytes)
This technical brief covers how Universal Serial Bus (USB) 2.0 products (PCI adapter cards, digital cameras, peripherals, etc.) can be susceptible to ESD events when the cable is disconnected from the data port. The ESD pulse can be introduced directly into the open port, or into the disconnected end of the cable and the integrated circuitry that controls the USB functionality can be compromised.
 
EC633 - ESD Protection Ethernet Data Lines
ec633.pdf (507,358 bytes)
This technical brief covers how Ethernet products (PCI adapter cards, hubs/routers, etc.) can be susceptible to ESD events when the cable is disconnected from the Ethernet port. The ESD pulse can be introduced directly into the open port, or into the disconnected end of the cable and the integrated circuitry that controls the Ethernet functionality can be compromised.
 
EC634 - General Purpose ESD Protection
ec634.pdf (137,763 bytes)
The purpose of this application brief is to detail (General Purpose) transient protection with signal bandwidth less than 125 Mbps and discusses how electronic systems are sensitive to both external and internal sources of overvoltage transients in the form of external Electro-Static Discharge (ESD) or internally generated Electrical Fast Transients (EFT).
 
EC635 - Designing with thermally protected TMOV Varistors in TVSS Applications
ec635.pdf (233,981 bytes)
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.
 
EC637 - Recommendations for Soldering Terminal Leads to MOV Varistor Discs
EC637.pdf (122,607 bytes)
This technical brief presents the CA and NA series of MOV varistor discs and discusses how they are specifically designed for custom assembly and packaging. It outlines how to take advantage of the excellent performance and reliability of Littelfuse varistor technology by choosing the correct materials and processes when soldering terminal leads to the disc.
 
EC638 - Littelfuse Varistor Design Examples
EC638.pdf (365,425 bytes)
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.
 
EC639 - AC Line Voltage Transients and Their Suppression
EC6391.pdf (166,822 bytes)
This application note covers the transient environment, transient energy and source impedance plus methods of suppression including, transient suppression, gas-tube arresters, zener diodes, metal oxide varistors and more.
 
EC640 - Combining GDTs and MOVs for Surge Protection of AC Lines
EC640.pdf (162,624 bytes)
This application note illustrates how to design high performance, cost-effective surge protection for equipment connected to AC power lines. The role of gas discharge tube (GDT) surge arresters specifically designed for AC power line protection is also be discussed.
 
EC641- Littelfuse Varistors: Connection and Terminology
EC641.pdf (188,798 bytes)
 
Triggering and Gate Characteristics of Thyristors
01_trigg.pdf (3,273,341 bytes)
 
TVS Diode/ SAD (Silicon Avalanche Diode) Application Note
TVS_app.pdf (91,624 bytes)
 
 Telecom
AN9108 - Littelfuse "ML" Multilayer Surface Mount Surge Suppressors
an9108.pdf (151,570 bytes)
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.
 
AN9768 - Transient Suppression Devices and Principles
an9768.pdf (128,962 bytes)
This application note discusses the two major categories of transient suppressors: a) those that attenuate transients, thus preventing their propagation into the sensitive circuit; and b) those that divert transients away from sensitive loads and so limit the residual voltages.
 
Analog Line Cards
3Analog.pdf (201,219 bytes)
Given that line cards are highly susceptible to transient voltages, network hazards such as lightning and power cross conditions pose a serious threat to equipment deployed at the central office and in remote switching locations. To minimize this threat, adequate levels of protection must be incorporated to ensure reliable operation and regulatory compliance.
 
CATV Equipment Protection
5CATV.pdf (112,151 bytes)
As cable providers enter the local exchange market, protection of CATV (Community Antenna TV) equipment becomes even more critical in order to ensure reliable operation of equipment and uninterrupted service.
 
Customer Premises Equipment (CPE)
1CPE.pdf (122,777 bytes)
CPE is defined as any telephone terminal equipment which resides at the customer's site and is connected to the Public Switched Telephone Network (PSTN). Telephones, modems, caller ID adjunct boxes, PBXs, and answering machines are all considered CPE.
 
Data Line Protectors
9DataLine.pdf (96,822 bytes)
In many office and industrial locations, data lines (such as RS-232 and ethernet) and AC power lines run in close proximity to each other, which often results in voltage spikes being induced onto the data line, causing damage to sensitive equipment.
 
EC606 - Protecting the Universal Serial Bus from Over Voltage and Overcurrent Threats
ec606.pdf (117,212 bytes)
This application note addresses the various requirements for protecting the Universal Serial Bus (USB) from overcurrent and over voltage environmental threats.The solutions presented cover both USB 1.1 and the higher speed USB 2.0 circuitry.
 
EC616 - Circuit Protection of USB 2.0
ec616.pdf (493,693 bytes)
This application brief demonstrates how to ensure reliable and safe circuit operation of USB products, protection against voltage and current transients must be carefully considered. Due to the higher data rates of USB 2.0, attention to the electrical characteristics of protection solutions is required.
 
EC621A - The ESD Problem
ec621a.pdf (173,377 bytes)
This technical brief defines Electrostatic Discharge(ESD), provides examples and discusses the issues surrounding protection against it.
 
EC622A - ESD Suppression Technologies
ec622a.pdf (176,397 bytes)
This technical brief discusses the three distinct Littelfuse product families that can be used for ESD suppression. These include the electroceramic MLV (MultiLayer Varistor), silicon (SP72x and SP050x) and polymer-based PulseGuard™ suppressor products.
 
EC623A - Selecting an ESD Suppressor
ec623a.pdf (149,769 bytes)
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.
 
EC624 - Capacitance and Signal Integrity
ec624.pdf (182,782 bytes)
This technical brief includes an introduction to capacitance to show that the capacitance characteristic is an important criterion when choosing an ESD suppressor. The effectiveness of ESD suppression technologies is not questioned here, rather it is noted that signal integrity can be compromised if capacitance is not taken into account.
 
EC628 - ESD Protection IEEE 1394 Data Lines
ec628.pdf (227,858 bytes)
This technical brief discusses how IEEE 1394 products (PCI adapter cards, hubs/routers, etc.) can be susceptible to ESD events when the cable is disconnected from the data port and how the integrated circuitry that controls the IEEE 1394 functionality can be compromised.
 
EC630 - ESD Protection USB 1.1 Data Lines
ec630.pdf (159,300 bytes)
This technical brief covers how Universal Serial Bus (USB) products (PCI adapter cards, digital cameras, peripherals, etc.) can be susceptible to ESD events when the cable is disconnected from the data port. The ESD pulse can be introduced directly into the open port, or into the disconnected end of the cable and the integrated circuitry that controls the USB functionality can be compromised.
 
EC631 - ESD Protection USB 2.0 Data Lines
ec631.pdf (221,196 bytes)
This technical brief covers how Universal Serial Bus (USB) 2.0 products (PCI adapter cards, digital cameras, peripherals, etc.) can be susceptible to ESD events when the cable is disconnected from the data port. The ESD pulse can be introduced directly into the open port, or into the disconnected end of the cable and the integrated circuitry that controls the USB functionality can be compromised.
 
EC633 - ESD Protection Ethernet Data Lines
ec633.pdf (507,358 bytes)
This technical brief covers how Ethernet products (PCI adapter cards, hubs/routers, etc.) can be susceptible to ESD events when the cable is disconnected from the Ethernet port. The ESD pulse can be introduced directly into the open port, or into the disconnected end of the cable and the integrated circuitry that controls the Ethernet functionality can be compromised.
 
EC634 - General Purpose ESD Protection
ec634.pdf (137,763 bytes)
The purpose of this application brief is to detail (General Purpose) transient protection with signal bandwidth less than 125 Mbps and discusses how electronic systems are sensitive to both external and internal sources of overvoltage transients in the form of external Electro-Static Discharge (ESD) or internally generated Electrical Fast Transients (EFT).
 
High Speed Transmission Equipment
2HighSpeed.pdf (151,531 bytes)
High speed transmission equipment encompasses a broad range of transmission protocols such as T1/E1, xDSL, and ISDN. Transmission equipment is located at the central office, customer premises, and remote locations.
 
LAN / WAN Protectors
10LANWAN.pdf (103,715 bytes)
 
PBX Systems
4PBX.pdf (127,321 bytes)
PBXs, KSUs, and PABXs contain line cards that support various transmission protocols such as ISDN, T1/E1, HDSL, and ADSL. PBXs also have features such as a POTS (plain old telephone service) pull-through which allows stations to have outside line access in the event of power failure. All incoming lines to the PBX are subject to environmental hazards such as lightning and power cross.
 
Primary Telecom Protection
6Primary.pdf (112,822 bytes)
Primary telecommunications protectors must be deployed at points where exposed twisted pairs enter an office building or residence. This requirement is mandated in North America by the National Electric Code (NEC) to protect end users from the hazards associated with lightning and power cross conditions.
 
Secondary Telecom Protection
7Secondary.pdf (133,008 bytes)
Secondary protectors (stand alone units or integrated into strip protectors and UPSs) are adjunct devices used to enhance the protection level of customer premise equipment (CPE). Due to the inadequate level of protection designed into CPE, secondary protectors often are required to prevent premature failure of equipment exposed to environmental hazards.
 
T1/E1/J1 Asymmetrical Protection
t1e1prot.pdf (68,870 bytes)
 
T3 Protection
t3prot.pdf (54,027 bytes)
 
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