Circuit Protection Products Selection Guide A guide to selecting the right protection components for your applications Design with Confidence Supported by our Deep Application Expertise and Extensive Portfolio About this guide This guide provides a summary of key circuit protection consideration factors, descriptions of the technologies Littelfuse offers, and product selection tables. It is designed to help you quickly find a protection solution appropriate to your application. Topic Page Littelfuse Circuit Protection Technologies 4–5 Overcurrent Protection Solutions 6 Overvoltage Protection Solutions 7 ESD Suppression Solutions 8 Applications 9–11 Common Circuit Threats and Protection Solutions 12–13 Fuses 14–16 Fuseholders 17 Surface Mount PPTC Devices 18–19 Radial Leaded PPTC Devices 19–20 Battery PPTC Devices 20 Battery Mini-Breakers (Thermal Cutoff Devices) 21 Telecom PPTC Devices 22 Varistors 23–24 Gas Discharge Tubes 24–26 PulseGuard® ESD Suppressors 26 TVS Diode Arrays 27–29 TVS Diodes 29–31 PLED Bypass Protectors 32–33 SIDACtor® Protection Thyristors 33–35 Specifications, descriptions, and illustrative material in this literature are as accurate as known at the time of publication, but are subject to changes without notice. Visit Littelfuse.com for more information. ©2020 Littelfuse, Inc. Testing Support Littelfuse: Everywhere, Every Day Littelfuse can help ensure that your products will withstand most Founded in 1927, Littelfuse has become the world’s most respected common threats repeatedly and will fail safely under extreme circuit protection brand, with well-established and growing circumstances. We can serve as an independent source to provide platforms in power control and sensing technologies. Today, we assistance as you design by offering lab testing capabilities for are a global company, offering a diverse and extensive product customer applications. This testing includes industry-specific portfolio—fuses, semiconductors, polymers, ceramics, relays, required power fault and Electrostatic Discharge (ESD) / Electrically sensors, and more—serving the electronics, automotive, and Fast Transients (EFT) / lightning surge conditions. industrial markets. Each is manufactured to exacting quality standards and backed by an unwavering commitment to technical Application Knowledge support and customer service. For over 90 years, Littelfuse has maintained a focus on circuit protection, and we will continue to adapt as technologies evolve. Engineers and Our history of innovation, combined with our customer-first circuit designers around the world have come to rely on Littelfuse culture, drives us to collaborate with you to develop safer, more products and application knowledge to support their designs. reliable products that are energy efficient and compliant with global regulations. We will partner with you to solve complex Global Support problems wherever electrical energy is used, bringing design, Littelfuse stays close to customers. With manufacturing, lab, and design engineering, and technical expertise to deliver business results. facilities located around the globe, application knowledge and technical support are locally available. Also, we offer a network of regional customer support offices and hundreds of independent authorized distributor contacts to assist you. Visit Littelfuse.com/contact-us to Why Choose Littelfuse find local support near you. Littelfuse is the global leader in circuit protection solutions. Standards Compliance Expertise We are the only company to offer all of the pertinent circuit Most Littelfuse products comply with a wide range of applicable protection technologies, with products that can be used in industry and government guidelines as well as our own rigorous virtually everything that uses electrical energy. Complementing quality and reliability criteria. We continually look forward and adapt to our wide portfolio of circuit protection products is a global changing requirements so that our products will comply with industry- network of design and technical support expertise. We offer specific national and international standards, such as CCC, CSA, IEC, decades of design experience to help you address IEEE, ISO, ITU, Meti, RoHs, Telcordia, TIA, and many more. application challenges and achieve regulatory compliance. Operational Excellence Your Single Source With our global manufacturing footprint, Littelfuse is firmly committed Littelfuse offers an extensive circuit protection product line. to manufacturing quality products at a competitive price. We build We design forward-thinking, application-specific solutions to quality into our products and services, striving for zero defects in provide assurance that your most demanding requirements everything we do, thereby reducing cost and increasing your total will be met. Our goal is to provide the most complete range of satisfaction. We strive to exceed your expectations every day. options so that you will not have to compromise. Quality Assurance 3 Our global manufacturing facilities abide by strict quality assurance requirements and hold the following quality management system registrations: • ISO 9001 • ISO14001 • IATF 16949 Littelfuse.com Circuit Protection Technologies Key Features and Protection When / Where Surge Energy Typical Voltage Typical Capacitance/ Mounting/Size/ Technology Characteristics Typically Used Rating Range Clamping Speeds Insertion Loss Packaging Options Overcurrent Protection Technologies Completely stops current flow, Ultimate protection for sensitive/ Low through Series impedance measured Very Extensive Fuses which helps to identify faults; Not applicable expensive/critical components Very High in nH Range of Options Wide range of options Resettable; No device Surface Mount, Where overcurrent events may occur Series resistance measured PPTC Devices replacement needed after most Low through High Not applicable Radial Leaded, often, and continuous uptime desired in ohms common overcurrent events Axial Strap Overvoltage Suppression Technologies Multi-Layer Varistors Compact and capable of handling ESD(1) and EFT(2) suppression in Miniature Low through Medium Moderate High (MLVs) significant surges for their size smaller and portable electronics Surface Mount Capable of withstanding very Metal-Oxide Varistors Appliance, industrial, and very high Medium through Radial Leaded, high energy transients; Moderate High (MOVs) energy suppression applications Very High Industrial Terminal Wide range of options Switches that turn to on state and Protection of Surface Mount, GDTs shunt overvoltage to ground using a telecom equipment Medium through High Fast Low Axial Leaded, contained inert gas as an insulator from lightning surges 2/3 Lead Radial Extremely low capacitance; ESD suppression; PulseGuard® ESD Miniature Fast response time; Ultra-fast reaction; Low Moderate Low Suppressors Surface Mount Compact size Low signal distortion PLED LED Shunt function bypasses open LEDs; High brightness outdoor Miniature Low Very Fast Medium Protectors ESD and reverse power protection LED lighting applications Surface Mount Low capacitance/ ESD suppression; Low distortion; Extensive range of TVS Diode Arrays low clamping voltage; Ideal for I/O interfaces and digital Low through Medium Very Fast Low surface mount options Compact size and analog signal lines Fast response to Semiconductor protection; fast transients; Telecom I/O interfaces, electronics, Axial Leaded, Radial TVS Diodes Medium through High Fast Medium Wide range of options: industrial equipment, and Leaded, Surface Mount No wear out mechanism automotive electronics Designed to comply with stringent telecom/datacom networking and Telecom/datacom and Extensive range SIDACtor® Protection industrial AC power surge protection networking applications, Medium through High Very Fast Medium - Low of surface mount and Thyristors 4 standards; No wear out mechanism, industrial equipment through-hole options precise trigger voltage, and very low Vt (1) ESD – Electrostatic Discharge (2) EFT – Electrical Fast Transient ©2020 Littelfuse, Inc. Fuses and Holders PulseGuard® ESD Fuses – Full range including surface mount, axial, glass or ceramic, thin-film or Nano2® style, fast- Suppressors acting or Slo-Blo® fuse. PulseGuard suppressors use polymer composite materials to suppress fast-rising ESD transients Clips – Used in applications that require a fuse while adding virtually no capacitance to the circuit. to be easily mounted to a Printed Circuit Board PulseGuard suppressors are best suited for low- (PCB), but real estate is scarce. Clips are also ideal voltage, high-speed applications such as protection for high-current applications, allowing for better for high-speed protocols like USB 2.0, IEEE1394, heat management of the fuse. They are the most HDMI, and Digital Visual Interface (DVI), where low economical solution. capacitance is important. Blocks – An alternative solution to clips but with easier placement on the PC board during manufacturing. In some instances, blocks may provide insulation to the side ears of the clips. In addition to being through-hole, blocks can also be Varistors screwed or riveted in place. Varistors are available in multiple forms, from Metal Oxide Varistors (MOVs) and Thermally Protected Holders – The ideal solutions for those applications MOV (TMOV® varistors) that suppress lightning that require the cartridge fuse to be protected, transient voltages to Multi-Layer Varistors (MLVs) providing a shock-safe environment. Panel-mount designed for applications