Expertise Applied | Answers Delivered Positive Temperature Coefficient (PTC)Thermistor Products

Littelfuse Circuit Prot Solutions Portf Consumer Electronics Telecom White Goods Medical Equipment TVSS and Power S DESIGN SUPPORT Live Application Design and Technical Support—Tap into our expertise. Littelfuse engineers are available around the world to help you address design challenges and develop unique, customized solutions for your products. Product Sampling Programs—Most of our products are available as samples for testing and verication within your circuit design. Visit Littelfuse.com or contact a Littelfuse product representative for additional information. Product Evaluation Labs and...

tection folio SWITCHING TECHNOLOGIES Supplies Lighting General Electronics Switching Thyristors— Solid-state switches used to control the ow of electrical current in applications, capable of withstanding rated blocking/ off-state voltage until triggered to on-state. In addition to our broad portfolio of circuit protection technologies, we offer an array of fuse holders including circuit board, panel or in-line wire mounted devices to support a wide range of application requirements. OVERCURRENT PROTECTION TECHNOLOGIES (7-8) 7. Positive Temperature Coefcient Devices (PTCs)— Provide resettable...

Positive Temperature Coefcient Thermistors (PTCs) Littelfuse PTCs offer a resettable over-current protection alternative. Ideal for situations where frequent over-current conditions occur or constant uptime is required, PTCs are typically used in consumer electronics, power line, telecom, I/O port, process control and medical equipment protection applications. PTCs increase resistance as temperature increases due to increased current ow. Designed to limit unsafe currents while allowing constant safe current levels, resistance will “reset” automatically when the fault is removed and temperature...

POLYFUSE® Resettable PTCs TABLE OF CONTENTS Introduction 2-3 Data Sheets: Surface Mount PTCs 9 Data Sheets: Radial Leaded PTCs 57 Data Sheets: Battery Strap PTCs LR Series, 1.90 – 7 .30A (Ihold) LT Series, 0.70 – 3.40A (Ihold) Battery Strap USBR Series, 0.75 – 2.50A (Ihold) Radial Leaded Surface Mount PTC Selection Worksheet & Product Tables

POLYFUSE® Resettable PTCs PTC Selection Worksheet 1. Dene the circuit operating parameters. Normal operating current in amperes: Normal operating voltage in volts: Maximum interrupt current: Ambient temperature: Typical overload current: Required opening time at specied overload: Transient pulses expected: Agency approvals: Mounting type/form factor: Typical resistance (in circuit): 2. Select the proper circuit protection component. (Refer to Table on Page 3 and specications with Data Sheets) 3. Determine the opening time at fault. Consult the Time-Current (T-C) Curve of each PTC series to determine...

POLYFUSE® Resettable PTCs PTC Selection Tables Surface Mount Type Series Chip Size Hold Current (IHOLD) Max Fault Current (IMAX) Operating Temperature Range Agency Approval RoHS Compliant Radial Leaded Type Series Hold Current (IHOLD) Max Fault Current (IMAX) Operating Temperature Range Agency Approval RoHS Compliant Battery Strap Type Series Hold Current (IHOLD) Max Fault Current (IMAX) Operating Temperature Range Agency Approval RoHS Compliant

POLYFUSE® Resettable PTCs Expertise Applied | Answers Delivered Overcurrent circuit protection can be accomplished with the use of either a traditional fuse or PTC (positive temperature coefficient) device. PTCs are typically used in a wide variety of telecom, computer, consumer electronics, battery and medical electronics product applications where overcurrent events are common and automatic resettability desired. Littelfuse offers PTCs with the following general forms and features, and come in a variety of sizes and capacities: Surface Mount Devices: • A full range of compact footprints • Very...

POLYFUSE® Resettable PTCs Leakage Current: When a PTC is in a "tripped state" it protects the circuitry by limiting the current ow to a low leakage level. Leakage current can range from less than a hundred milliamps (mA) at rated voltage up to a few hundred milliamps (mA) at lower voltages. Fuses on the other hand completely interrupt the current ow when tripped, and this open circuit results in no leakage current when subjected to an overload current. Time-Current Characteristic: Comparing the timecurrent curves of PTCs to time-current curves of fuses show that the speed of response for a PTC...

POLYFUSE® Resettable PTCs PTC Product Applications PTCs are typically used as circuit protection in applications where sensitive components are at constant risk of damage from overcurrent conditions. The ability of PTCs to reset themselves after exposure to a fault current makes them ideal within circuits that are not easily accessible to a user or technician or where constant uptime is required. The chart below is meant as a quick guide in narrowing to a Littelfuse PTC device that may be appropriate to certain end applications. For detailed application assistance please contact a Littelfuse...

POLYFUSE® Resettable PTCs Typical PTC Circuit Protection Designs The following are examples of typical circuits using Littelfuse PTCs in combination with other Littelfuse circuit protection devices to provide a comprehensive protection solution. Contact a Littelfuse application expert for design assistance or visit www.littelfuse.com/designcenter or http://www.littelfuse.com/PTCs for additional information. Be sure to to veryify specications and test device performance before use in the end application. POWER OVER ETHERNET LI-ION BATTERY PACK Battery Connector Data Pair Data Pair Cell Phone Power...

Expertise Applied | Answers Delivered POLYFUSE® Resettable PTCs Surface Mount > 0603L Series Agency Approvals AGENCY AGENCY FILE NUMBER The new 0603L Series PTC provides surface mount overcurrent protection for applications where space is at a premium and resettable protection is desired • Fast response to fault • Compact design saves board space • Disk drives • Plug and play protection • Compatible with high temperature solders • PDAs/ digital cameras • Game console port Electrical Characteristics I ho|d = Hold current: maximum current device will pass without tripping in 20°C still air I tMp...