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POLY-FUSE® Resettable PTCs Littelfuse* Expertise Applied | Answers Delivered TABLE OF CONTENTS PTC Characteristics and Terms PTC Applications & Typical PTC Circuit Protection Design PTC Selection Worksheet Legal Disclaimers

POLY-FUSE® 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 from...

POLY-FUSE® Resettable PTCs PTC Characteristics and Terms (continued) Leakage Current: When a PTC is in a "tripped state" it protects the circuitry by limiting the current flow 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 flow 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...

POLY-FUSE® Resettable PTCs Expertise Applied | Answers Delivered 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. Typical applications include port protection on personal computers (USB, memory card reader, keyboard/mouse and video ports), peripherals (hard drives, video cards, and hubs), cell phone,...

POLY-FUSE® 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 specifications 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...

POLY-FUSE® Resettable PTCs PTC Selection Worksheet 1. Define 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 specified overload: Transient pulses expected: approvals: Agency Mounting type/form factor: Typical resistance (in circuit): 2. Select the proper circuit protection component. (Refer to Table on Page 3 and specifications with Data Sheets) 3. Determine the opening time at fault. Consult the Time-Current (T-C) Curve of each PTC series...

POLY-FUSE® Resettable PTCs Legal Disclaimers Liability Littelfuse, Inc. its affiliates, agents, and employees, and all persons acting on its or their behalf (collectively, “Littelfuse”), disclaim any and all liability for any errors, inaccuracies or incompleteness contained here or in any other disclosure relating to any product. Littelfuse disclaims any and all liability arising out of the use or application of any product described herein or of any information provided herein to the maximum extent permitted by law. The product specifications do not expand or otherwise modify Littelfuse terms...

Llttelfuse* Expertise Applied | Answers Delivered POLY-FUSE® Resettable PTCsSurface Mount > LoRho SeriesLoRho Surface Mount Series [RQhs Pb c' Agency Approvals Littelfuse LoRho Surface Mount PPTC (Polymer Positive Temperature Coefficient) devices provide overcurrent protection for applications where ultra low internal resistance, ultra low voltage drop and automatic resettable protection are desired. This new series allows a higher hold current device in a smaller factor and lower profile as compared to a standard PPTC. It offers ultra low internal resistance while maintaining the high level...

Llttelfuse* Expertise Applied | Answers Delivered POLY-FUSE® Resettable PTCs Surface Mount > LoRho Series Electrical Characteristics Notes: 0805L150SL and 1206L150SL are ideal for overcurrent protection in VBUS of USB 3.0 / USB 2.0 ports. * 1206L380SLTH has ^ 2.82A for at least 15min @ 55°C. It is ideal for overcurrent protection in Li-ion / Li-Polymer battery packs of smartphones. ** 1812L350SL Typical Time-To-Trip is 50A at 0.013-0.020 seconds. R1min=0.015ohm (resistance range 0.015-0.025ohm). *** 2920L700SL is ideal for overcurrent protection in Li-ion / Li-Polymer battery packs of tablet...

Littelfuse* Expertise Applied | Answers Delivered POLY-FUSE® Resettable PTCsSurface Mount > LoRho SeriesTemperature Rerating Ambient Operation Temperature Part Number Hold Current (A) Notes: The temperature rerating data is for reference only. Please contact Littelfuse technical support for detail temperature rerating information. © 2015 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 11/05/15

POLY-FUSE® Resettable PTCs Surface Mount > LoRho Series Environmental Specifications Temperature Rerating Curve Operating Temperature 150% Percentage of Rated Current Maximum Device Surface Temperature in Tripped State Passive Aging +85°C, 1000 hours -/+10% typical resistance change Humidity Aging +85°C, 85% R.H.,100 hours -/+15% typical resistance change Thermal Shock MIL–STD–202, Method 107 +85°C/-40°C 20 times -30% typical resistance change Solvent Resistance MIL–STD–883, Method 2007 , Condition A No change Moisture Sensitivity Level Physical Specifications Terminal Material Solder-Plated...