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Littelfuse Polyfuse PTC Selection Guide

Littelfuse Polyfuse PTC Selection Guide
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Littelfuse Polyfuse PTC Selection Guide - 1

that the circuit parameters do not exceed these ratings. Determine the following circuit operating parameters: 4. Verify that the ambient operating temperature within close proximity to the device is within its normal operating range. Thermally derate IHOLD and IMAX as necessary. See equation below. • Normal operating current – IHOLD • Maximum circuit voltage – VMAX • Maximum interrupt current – IMAX • Ambient operating temperature 2. Select the suitable form factor. 3. Compare the PTC data sheet ratings on littelfuse.com for VMAX and IMAX to ensure 5. Check that the trip time protects the circuit. 6. Verify that the post trip resistance (R1MAX) of the device is taken into account in the circuit design. 7. Independently test and evaluate the suitability and performance of the PTC in the actual application. Thermal derating factor RADIAL LEADED International Sales, Distribution and Engineering Facilities: Chip Size Hold Current (IHOLD) Max fault current (IMAX) Agency approval RoHS Compliant Operating Temperature Range World Headquarters Littelfuse, Inc. 800 E. Northwest Highway Des Plaines, IL 60016 USA www.littelfuse.com PTC Selection Table Series Name POLYFUSE® PTC SELECTION GUIDE COMPETITOR CROSS Tyco/Raychem Series Bourns Series North America • Birmingham, Michigan USA Des Plaines, Illinois USA and Irving, Texas USA Technical Assistance Phone: 800 999 9445 847 824 1188 Fax: 847 391 0459 Europe • Dünsen, Germany Phone: +49 4244 8190 Fax: +49 4244 819 139 • Munich, Germany Phone: +49 8955 27660 Fax: +49 8955 276 699 PTC Selection Table (cont.) BATTERY STRAP (AXIAL LEADED) Series Name Max fault current (IMAX) Chip Size Hold Current (IHOLD) Asia/Pacic • Hong Kong, China Phone: +852 2810 5099 Fax: +852 2810 5500 Operating Temperature Range Agency approval RoHS Compliant COMPETITOR CROSS Tyco/Raychem Series Amp Rating Max voltage Bourns Series FORM NO. EC327-E © November 2006, Littelfuse Inc. Printed in U.S.A. Specifications, descriptions and illustrative material in this literature are as accurate as known at the time of publication, but are subject to change without notice. Research and Manufacturing Facilities: • Arcola, Illinois USA • Des Plaines, Illinois USA • Dongguan, China • Dundalk, Ireland • Dünsen, Germany • Irving, Texas USA • Lipa City, Philippines • Matamoros, Mexico • Piedras Negras, Mexico • Suzhou, China • Swindon, England • Witten, Germany • Wuxi, China • Yangmei, Taiwan Surface Mount Battery Strap Radial Leaded High Voltage Radial Leaded

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Littelfuse Polyfuse PTC Selection Guide - 2

Recognized under the Component Program of Underwriters Laboratories to UL Standard 1434 for Thermistors. The devices have also been approved for use in Canada by Underwriters Laboratories. Approvals for fuses include Recognition under the Component Program of Underwriters Laboratories and the CSA Component Acceptance Program. In addition, many fuses are listed in accordance with UL/CSA/ANCE (Mexico) 248-14, Supplemental Fuses. ITU-T Recoomendations CPE (Customer Premises Equipment) The terminology used for PTCs is often similar but not the same as for fuses. Two parameters that fall into...

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