that the circuit parameters do not exceed 5. Check that the trip time protects Selection Process these ratings. the circuit. 1. Determine the following circuit operating 4. Verify that the ambient operating 6. Verify that the post trip resistance (R1 ) MAX parameters: temperature within close proximity to of the device is taken into account in the  Normal operating current – I HOLD the device is within its normal operating circuit design.  Maximum circuit voltage – V MAX ® POLYFUSE PTC SELECTION GUIDE  Maximum interrupt current – I MAX range. Thermally derate I and I as HOLD MAX 7. Independently test and evaluate the  Ambient operating temperature necessary. See equation below. suitability and performance of the PTC 2. Select the suitable form factor. in the actual application. I World Headquarters 3. Compare the PTC data sheet ratings on MAX I = HOLD littelfuse.com for V and I to ensure Thermal derating factor Littelfuse, Inc. MAX MAX 800 E. Northwest Highway Des Plaines, IL 60016 USA PTC Selection Table www.littelfuse.com SURFACE MOUNT RADIAL LEADED Series Name 0805L 1206L 1210L 1812L 2016L 2920L USBR 30R International Sales, Asia/PaciŢ c Research and Distribution and Manufacturing Facilities:  Hong Kong, China Photos Engineering Facilities: Phone: +852 2810 5099  Arcola, Illinois USA Fax: +852 2810 5500  Des Plaines, Illinois USA North America Chip Size 0805 (2012) 1206 (3216) 1210 (3225) 1812 (4532) 2016 (5041) 2920 (7351)  Dongguan, China  Birmingham, Michigan USA  Beijing, China Hold Current (I ) 0.10-1.00A 0.125-2.00A 0.05-1.75A 0.10-2.60A 0.3-2.00A 0.30-3.00A 0.75-2.5A 0.9-9.00A HOLD Des Plaines, Illinois USA Phone: +86 10 8454 9408  Dundalk, Ireland Max voltage (V ) 15V 30V 30V 60V 60V 60V 16V 30V MAX and Irving, Texas USA Fax: +86 10 8454 9409  Dünsen, Germany Max fault current (I ) 40A 100A 100A 100A 40A 40A 40A 40A MAX Technical Assistance  Irving, Texas USA  Shanghai, China Operating Temperature Range -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C Phone: 800 999 9445  Lipa City, Philippines Phone: +86 21 5383 8016 Agency approval cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV 847 824 1188 Fax: +86 21 5383 7476  Matamoros, Mexico Fax: 847 391 0459 RoHS Compliant Yes Yes Yes Yes Yes Yes Yes Yes  Piedras Negras, Mexico  Shenzhen, China Lead-Free Yes Yes Yes Yes Yes Yes Yes Yes Europe  Suzhou, China Phone: +86 755 8207 0760 COMPETITOR CROSS Surface Mount  Dünsen, Germany  Swindon, England Fax: +86 755 8207 0759 Tyco/Raychem Series nano SMD micro SMD mini SMD mid SMD SMD RUSB RUE Phone: +49 4244 8190  Witten, Germany Amp Rating NA 0.500-1.50A 0.050-1.50A 0.140-2.60A 0.300-2.00A 0.300-3.00A 0.750-2.50A 0.900-9.00A Fax: +49 4244 819 139  Singapore Battery Strap  Wuxi, China Max voltage NA 6V 6-30V 6-60V 6-60V 6-60V 16V 30V Phone: +65 6885 9111  Munich, Germany  Yangmei, Taiwan Fax: +65 6885 9113 Bourns Series MF-NSMF MF-USMD MF-MSMD MF-SMDF MF-SM MF-R Radial Leaded Phone: +49 8955 27660 Amp Rating NA 0.12-2.00 0.05-1.50A 0.05-1.50A 0.55-2.00A 0.300-2.5A NA 0.90-9.0A  Yokohama, Japan Fax: +49 8955 276 699 High Voltage Max voltage NA 6-30V 6-30V 6-30V 10-60V 6-60V NA 30V Phone: +81 45 478 1088  Utrecht, The Netherlands Radial Leaded NO = Not offered Fax: +81 45 478 1089 Phone: +31 30 299 9900 Fax: +31 30 299 9800  Seoul, Korea PTC Selection Table (cont.) Phone: +82 2 6000 8600  Swindon, England BATTERY STRAP (AXIAL LEADED) Fax: +82 2 6000 8655 Phone: +44 1793 720770 Series Name 60R 250R 600R ST LT LR VT VL  Taipei, Taiwan Fax: +44 1793 720771 Phone: +886 2 8751 1234 Fax: +886 2 8751 1177 Photos Central and South America  São Paulo, Brasil Chip Size Phone: +55 113 835 3780 Hold Current (I ) 0.1-3.75A 0.08-0.18A 0.15-0.16A 1.2-4.2A 0.7-3.4A 1.9-10.00A 1.7-2.4A 1.7-2.3A HOLD Fax: +55 113 645 0612 Max voltage (V ) 60V 60/250V 60/600V 15/24V 15/24V 15/20V 16V 12V MAX Max fault current (I ) 40A 3/10A 3/2.2A 100A 100A 100A 100A 100A MAX Operating Temperature Range -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C Agency approval cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV RoHS Compliant Yes Yes Yes Yes Yes Yes Yes Yes Lead-Free Yes Yes Yes Yes Yes Yes Yes Yes COMPETITOR CROSS Tyco/Raychem Series RXE TR250 TR600 SRP LTP LR4 VTP VLR Amp Rating 0.100-3.75A 0.080-0.180A 0.150-0.160A 1.20-4.20A 0.700-3.40A 1.7-13A 1.10-2.40A 2.10-2.30A Max voltage 60-72V 60/250V 60/600V 15/30V 24V 15/20V 16V 16V Bourns Series MF-R/MF-RX MF-R/250 MF-R/600 MF-S MF-LS MF-LR MF-VS FORM NO. EC327-E © November 2006, Littelfuse Inc. Printed in U.S.A. Amp Rating 0.10-3.75A 0.08-0.18A 0.15-0.16A 1.2-4.2A 0.70-3.4A 1.9-9.0A 1.7-2.4A NA Specifications, descriptions and illustrative material in this literature are as accurate as known at the time of Max voltage 60V 60/250V 60/600V 15-30V 15-24V 15-20V 16V NA publication, but are subject to change without notice. NA = Not Available 5 LEAKAGE CURRENT: A PTC is said to TEMPERATURE DERATING: The useful When to apply a resettable PTC vs. a Systems Interface) Standard for this large Littelfuse offers a full range of battery required. The following are typical examples complete protection for the circuit. Contact PTC Characteristics PTC Applications ® have “tripped” when it has transitioned upper limit for a PTC is generally 85°C while traditional fuse is always the choice of the market includes a statement that “....a strap, surface mount and radial leaded of circuits using POLYFUSE resettable your location Littelfuse application expert and Terminology PTCs are used as circuit protection in from its low resistance state to a high the maximum operating temperature for designer or technician but in some cases, Positive Temperature Coeffi cient device resettable PTC devices designed to protect PTCs in combination with other Littelfuse for additional design assistance or applications where sensitive components resistance state due to overload current. fuses is 125°C. The following temperature PTC’s offer a convenient form of circuit must be used instead of a fuse, to limit the applications where overcurrent protection is circuit protection devices to provide visit www.littelfuse.com/PTCs. A polymeric PTC (positive temperature are at risk of damage from overcurrent derating curves (see chart at bottom of protection to improve the reliability of an maximum amount of current sourced”. coeffi cient) overcurrent protector is an Protection is accomplished by limiting the conditions. The ability of PTCs to reset page) that compare PTCs to fuses illustrate application. There is an important area of element placed in series with the circuit or current fl ow to a low leakage level. Leakage The application selection guide below should themselves after exposure to a fault current that more derating is required for a PTC at a applications where the use of resettable assembly to be protected. The PTC current can range from less than a hundred be used as an aid in selecting the proper Power Over Ethernet Li-ion Battery Pack makes them ideal for use in circuits that are given temperature. fuses (PTCs) has become a requirement. element protects the circuit by changing milliamps at rated voltage up to a few device for your end application. Please not easily accessible to a user or technician. Much of the design work for personal Swtich/Hub Powered End Station from a low-resistance to a high resistance hundred milliamps at lower voltages. Additional operating characteristics can be consult the datasheets on www.littelfuse.com Typical applications include port protection Battery Connector Battery Controller IC computers and peripheral devices is state in response to an overcurrent. The fuse on the other hand completely reviewed by the circuit designer in making for detailed technical specifi cations. on personal computers (USB, Firewire, strongly infl uenced by the Microsoft and Data Pair Data Pair interrupts the current fl ow and this open the decision to choose a PTC or a fuse for keyboard/mouse, and serial ports), Battery + This function is called “tripping” of the Intel System Design Guide which states circuit results in no leakage current after it overcurrent protection. Battery - peripherals (hard drives, video cards, and overcurrent protection device. that “Using a fuse that must be replaced has been subjected to an overload current. Control hubs), cell phone, battery packs, industrial each time an overcurrent condition occurs is AGENCY APPROVALS: PTCs are Overcurrent circuit protection can be controls, lighting ballast and motor controls. unacceptable.” And the SCSI (Small Computer Power Source Powered FAULT CURRENT: The PTC is rated for Recognized under the Component accomplished with the use of either a Equipment Device a maximum short circuit current at rated Program of Underwriters Laboratories to (3) V5.5MLA0402 (PSE) (PD) traditional fuse or the more recently SURFACE MOUNT RADIAL LEADED BATTERY STRAP (AXIAL LEADED) (Multilayer voltage. This fault current level is the UL Standard 1434 for Thermistors. developed resettable PTC. Both devices Varistor) Series Name 0805L 1206L 1210L 1812L 2016L 2920L USBR 30R 60R 250R 600R ST LT LR VT VL Signal maximum current that the device can safely The devices have also been approved for function by reacting to the heat generated Ground Application limit keeping in mind that the PTC will not use in Canada by Underwriters Laboratories. by the excessive current fl ow in the circuit. Ul60950 ,TIA-968-A, GR-1089 Requirements XX Data Pair Data Pair Shield actually interrupt the current fl ow (see Approvals for fuses include Recognition The fuse element melts open, interrupting ITU-T Recoomendations XX Ground LEAKAGE CURRENT above). The typical under the Component Program of the current fl ow, while the PTC changes CPE (Customer Premises Equipment) XX short circuit rating of a board-mounted PTC Underwriters Laboratories and the CSA Analog Line Card XX from low resistance to high resistance is 40A; for battery strap PTCs, this value can Component Acceptance Program. In addition, T1/E1/J1 And HDSL XX to limit current fl ow. The graph below reach 100A. Fuses do in fact interrupt the many fuses are listed in accordance with ISDN XX shows the response of the PTC device USB 1.1 USB 2.0 ADSL XX current fl ow in response to the overload and UL/CSA/ANCE (Mexico) 248-14, to temperature. Cable Telephony XX the range of interrupting ratings vary from Supplemental Fuses. PBX/KTS And Key Telephone System XX USB Port USB Controller USB Port USB Controller tens of amperes up to 10,000 amperes at CPU XX RESISTANCE: Reviewing product V5.5MLA0603 V5.5MLA0603 V5.5MLA063 rated voltage. USB XXXX X specifi cations indicates that similarly-rated VBU VBUS IEEE1284 Parallel Data Bus XXX X 1206L150 1206L150 OPERATING VOLTAGE RATING: PTCs have about twice (sometimes more) D+ D+ IEEE 802.3 XX X D - D - General use PTCs are not rated above 60V the resistance of fuses. IEEE 1394 XXX while fuses are rated up to 600V. I/O Ports XXX X X TIME-CURRENT CHARACTERISTIC: PC Card XXXX XX (2) V0402MHS03 (2) PGB1010603 HOLD CURRENT RATING: The hold Comparing the time-current curves of PTCs ® SCSI XXX X X (PulseGuard (operating) current rating for PTCs can be to time-current curves of fuses show that ESD Suppressor) Video Port XXX X X Signal Signal up to 14A while the maximum level for the speed of response for a PTC is similar LCD Monitor XXXX X Ground Ground Trip Point ® fuses can exceed 30A. to the time delay of a Slo-Blo fuse. Set Top Box XXX X Shield Shield Loudspeaker X Temperature (°C) Ground Ground Smart Card Reader X Mobile Phone XXX Temperature Derating Curves Comparing PTCs to Fuses Understanding the differences in Linear AC/DC Adapter XXXX X X X Chart Key C Portable Electronic Input Port XXXXX performance between the two types of 140 Electromagnetic Loads, Motor XX XX IEEE 1394 – FireWire Tip/Ring circuit – Metallic devices will make the best circuit protection Curve A Solenoid Protection XXXX choice easier. The most obvious difference Thin-Film Fuses and 313 120 A XXXXX Lithium Cell Series (.010 to .150A) is that the PTC is resettable. This is an 1394 Port 1394 Controller RJ11 Connector Tx/Rx Circuits B XXXXX V33MLA1206 inherent characteristic in which the PTC Battery Pack 100 Curve B B ® ® resets (returns to low resistance state) VBU FLAT-PAK , Telelink , 1812L110/33 2® ® after power is removed and the device Nano , PICO , TPA+ Tip 80 Voltage / Current Input Terminal XX TPA- Blade Terminal, cools down. There are a number of other A TPB+ Special Purpose and 600R Series SMD/leaded operating characteristics that differentiate 60 TPB- ® 250R Series SIDACtor other leaded and NOTE: The application summary is for reference only. Determination of suitability for a specific application is the responsibility of the customer. the two types of products. Device cartridge fuses 25°C 40 (except 313.010 – .150A) C Ring The terminology used for PTCs is often (4) PGB1010603 Signal Signal Curve C similar but not the same as for fuses. Two 20 ® Ground Ground (PulseGuard Resettable PTCs parameters that fall into this category are ESD Suppressor) -60°C -40°C -20°C 0°C 20°C 40°C 60°C 80°C 100°C 120°C Shield leakage current and fault current rating. -76°F -40°F -4°F 32°F 68°F 104°F 140°F 176°F 212°F 248°F Ground AMBIENT TEMPERATURE 2 3 4 Log resistance (ohms) PERCENT OF RATING Medical Consumer Battery Computer Telecom electronic Electronics Outside World Outside World Telco Outside World Cell Phone that the circuit parameters do not exceed 5. Check that the trip time protects Selection Process these ratings. the circuit. 1. Determine the following circuit operating 4. Verify that the ambient operating 6. Verify that the post trip resistance (R1 ) MAX parameters: temperature within close proximity to of the device is taken into account in the  Normal operating current – I HOLD the device is within its normal operating circuit design.  Maximum circuit voltage – V MAX ® POLYFUSE PTC SELECTION GUIDE  Maximum interrupt current – I MAX range. Thermally derate I and I as HOLD MAX 7. Independently test and evaluate the  Ambient operating temperature necessary. See equation below. suitability and performance of the PTC 2. Select the suitable form factor. in the actual application. I World Headquarters 3. Compare the PTC data sheet ratings on MAX I = HOLD littelfuse.com for V and I to ensure Thermal derating factor Littelfuse, Inc. MAX MAX 800 E. Northwest Highway Des Plaines, IL 60016 USA PTC Selection Table www.littelfuse.com SURFACE MOUNT RADIAL LEADED Series Name 0805L 1206L 1210L 1812L 2016L 2920L USBR 30R International Sales, Asia/PaciŢ c Research and Distribution and Manufacturing Facilities:  Hong Kong, China Photos Engineering Facilities: Phone: +852 2810 5099  Arcola, Illinois USA Fax: +852 2810 5500  Des Plaines, Illinois USA North America Chip Size 0805 (2012) 1206 (3216) 1210 (3225) 1812 (4532) 2016 (5041) 2920 (7351)  Dongguan, China  Birmingham, Michigan USA  Beijing, China Hold Current (I ) 0.10-1.00A 0.125-2.00A 0.05-1.75A 0.10-2.60A 0.3-2.00A 0.30-3.00A 0.75-2.5A 0.9-9.00A HOLD Des Plaines, Illinois USA Phone: +86 10 8454 9408  Dundalk, Ireland Max voltage (V ) 15V 30V 30V 60V 60V 60V 16V 30V MAX and Irving, Texas USA Fax: +86 10 8454 9409  Dünsen, Germany Max fault current (I ) 40A 100A 100A 100A 40A 40A 40A 40A MAX Technical Assistance  Irving, Texas USA  Shanghai, China Operating Temperature Range -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C Phone: 800 999 9445  Lipa City, Philippines Phone: +86 21 5383 8016 Agency approval cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV 847 824 1188 Fax: +86 21 5383 7476  Matamoros, Mexico Fax: 847 391 0459 RoHS Compliant Yes Yes Yes Yes Yes Yes Yes Yes  Piedras Negras, Mexico  Shenzhen, China Lead-Free Yes Yes Yes Yes Yes Yes Yes Yes Europe  Suzhou, China Phone: +86 755 8207 0760 COMPETITOR CROSS Surface Mount  Dünsen, Germany  Swindon, England Fax: +86 755 8207 0759 Tyco/Raychem Series nano SMD micro SMD mini SMD mid SMD SMD RUSB RUE Phone: +49 4244 8190  Witten, Germany Amp Rating NA 0.500-1.50A 0.050-1.50A 0.140-2.60A 0.300-2.00A 0.300-3.00A 0.750-2.50A 0.900-9.00A Fax: +49 4244 819 139  Singapore Battery Strap  Wuxi, China Max voltage NA 6V 6-30V 6-60V 6-60V 6-60V 16V 30V Phone: +65 6885 9111  Munich, Germany  Yangmei, Taiwan Fax: +65 6885 9113 Bourns Series MF-NSMF MF-USMD MF-MSMD MF-SMDF MF-SM MF-R Radial Leaded Phone: +49 8955 27660 Amp Rating NA 0.12-2.00 0.05-1.50A 0.05-1.50A 0.55-2.00A 0.300-2.5A NA 0.90-9.0A  Yokohama, Japan Fax: +49 8955 276 699 High Voltage Max voltage NA 6-30V 6-30V 6-30V 10-60V 6-60V NA 30V Phone: +81 45 478 1088  Utrecht, The Netherlands Radial Leaded NO = Not offered Fax: +81 45 478 1089 Phone: +31 30 299 9900 Fax: +31 30 299 9800  Seoul, Korea PTC Selection Table (cont.) Phone: +82 2 6000 8600  Swindon, England BATTERY STRAP (AXIAL LEADED) Fax: +82 2 6000 8655 Phone: +44 1793 720770 Series Name 60R 250R 600R ST LT LR VT VL  Taipei, Taiwan Fax: +44 1793 720771 Phone: +886 2 8751 1234 Fax: +886 2 8751 1177 Photos Central and South America  São Paulo, Brasil Chip Size Phone: +55 113 835 3780 Hold Current (I ) 0.1-3.75A 0.08-0.18A 0.15-0.16A 1.2-4.2A 0.7-3.4A 1.9-10.00A 1.7-2.4A 1.7-2.3A HOLD Fax: +55 113 645 0612 Max voltage (V ) 60V 60/250V 60/600V 15/24V 15/24V 15/20V 16V 12V MAX Max fault current (I ) 40A 3/10A 3/2.2A 100A 100A 100A 100A 100A MAX Operating Temperature Range -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C Agency approval cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV RoHS Compliant Yes Yes Yes Yes Yes Yes Yes Yes Lead-Free Yes Yes Yes Yes Yes Yes Yes Yes COMPETITOR CROSS Tyco/Raychem Series RXE TR250 TR600 SRP LTP LR4 VTP VLR Amp Rating 0.100-3.75A 0.080-0.180A 0.150-0.160A 1.20-4.20A 0.700-3.40A 1.7-13A 1.10-2.40A 2.10-2.30A Max voltage 60-72V 60/250V 60/600V 15/30V 24V 15/20V 16V 16V Bourns Series MF-R/MF-RX MF-R/250 MF-R/600 MF-S MF-LS MF-LR MF-VS FORM NO. EC327-E © November 2006, Littelfuse Inc. Printed in U.S.A. Amp Rating 0.10-3.75A 0.08-0.18A 0.15-0.16A 1.2-4.2A 0.70-3.4A 1.9-9.0A 1.7-2.4A NA Specifications, descriptions and illustrative material in this literature are as accurate as known at the time of Max voltage 60V 60/250V 60/600V 15-30V 15-24V 15-20V 16V NA publication, but are subject to change without notice. NA = Not Available 5 LEAKAGE CURRENT: A PTC is said to TEMPERATURE DERATING: The useful When to apply a resettable PTC vs. a Systems Interface) Standard for this large Littelfuse offers a full range of battery required. The following are typical examples complete protection for the circuit. Contact PTC Characteristics PTC Applications ® have “tripped” when it has transitioned upper limit for a PTC is generally 85°C while traditional fuse is always the choice of the market includes a statement that “....a strap, surface mount and radial leaded of circuits using POLYFUSE resettable your location Littelfuse application expert and Terminology PTCs are used as circuit protection in from its low resistance state to a high the maximum operating temperature for designer or technician but in some cases, Positive Temperature Coeffi cient device resettable PTC devices designed to protect PTCs in combination with other Littelfuse for additional design assistance or applications where sensitive components resistance state due to overload current. fuses is 125°C. The following temperature PTC’s offer a convenient form of circuit must be used instead of a fuse, to limit the applications where overcurrent protection is circuit protection devices to provide visit www.littelfuse.com/PTCs. A polymeric PTC (positive temperature are at risk of damage from overcurrent derating curves (see chart at bottom of protection to improve the reliability of an maximum amount of current sourced”. coeffi cient) overcurrent protector is an Protection is accomplished by limiting the conditions. The ability of PTCs to reset page) that compare PTCs to fuses illustrate application. There is an important area of element placed in series with the circuit or current fl ow to a low leakage level. Leakage The application selection guide below should themselves after exposure to a fault current that more derating is required for a PTC at a applications where the use of resettable assembly to be protected. The PTC current can range from less than a hundred be used as an aid in selecting the proper Power Over Ethernet Li-ion Battery Pack makes them ideal for use in circuits that are given temperature. fuses (PTCs) has become a requirement. element protects the circuit by changing milliamps at rated voltage up to a few device for your end application. Please not easily accessible to a user or technician. Much of the design work for personal Swtich/Hub Powered End Station from a low-resistance to a high resistance hundred milliamps at lower voltages. Additional operating characteristics can be consult the datasheets on www.littelfuse.com Typical applications include port protection Battery Connector Battery Controller IC computers and peripheral devices is state in response to an overcurrent. The fuse on the other hand completely reviewed by the circuit designer in making for detailed technical specifi cations. on personal computers (USB, Firewire, strongly infl uenced by the Microsoft and Data Pair Data Pair interrupts the current fl ow and this open the decision to choose a PTC or a fuse for keyboard/mouse, and serial ports), Battery + This function is called “tripping” of the Intel System Design Guide which states circuit results in no leakage current after it overcurrent protection. Battery - peripherals (hard drives, video cards, and overcurrent protection device. that “Using a fuse that must be replaced has been subjected to an overload current. Control hubs), cell phone, battery packs, industrial each time an overcurrent condition occurs is AGENCY APPROVALS: PTCs are Overcurrent circuit protection can be controls, lighting ballast and motor controls. unacceptable.” And the SCSI (Small Computer Power Source Powered FAULT CURRENT: The PTC is rated for Recognized under the Component accomplished with the use of either a Equipment Device a maximum short circuit current at rated Program of Underwriters Laboratories to (3) V5.5MLA0402 (PSE) (PD) traditional fuse or the more recently SURFACE MOUNT RADIAL LEADED BATTERY STRAP (AXIAL LEADED) (Multilayer voltage. This fault current level is the UL Standard 1434 for Thermistors. developed resettable PTC. Both devices Varistor) Series Name 0805L 1206L 1210L 1812L 2016L 2920L USBR 30R 60R 250R 600R ST LT LR VT VL Signal maximum current that the device can safely The devices have also been approved for function by reacting to the heat generated Ground Application limit keeping in mind that the PTC will not use in Canada by Underwriters Laboratories. by the excessive current fl ow in the circuit. Ul60950 ,TIA-968-A, GR-1089 Requirements XX Data Pair Data Pair Shield actually interrupt the current fl ow (see Approvals for fuses include Recognition The fuse element melts open, interrupting ITU-T Recoomendations XX Ground LEAKAGE CURRENT above). The typical under the Component Program of the current fl ow, while the PTC changes CPE (Customer Premises Equipment) XX short circuit rating of a board-mounted PTC Underwriters Laboratories and the CSA Analog Line Card XX from low resistance to high resistance is 40A; for battery strap PTCs, this value can Component Acceptance Program. In addition, T1/E1/J1 And HDSL XX to limit current fl ow. The graph below reach 100A. Fuses do in fact interrupt the many fuses are listed in accordance with ISDN XX shows the response of the PTC device USB 1.1 USB 2.0 ADSL XX current fl ow in response to the overload and UL/CSA/ANCE (Mexico) 248-14, to temperature. Cable Telephony XX the range of interrupting ratings vary from Supplemental Fuses. PBX/KTS And Key Telephone System XX USB Port USB Controller USB Port USB Controller tens of amperes up to 10,000 amperes at CPU XX RESISTANCE: Reviewing product V5.5MLA0603 V5.5MLA0603 V5.5MLA063 rated voltage. USB XXXX X specifi cations indicates that similarly-rated VBU VBUS IEEE1284 Parallel Data Bus XXX X 1206L150 1206L150 OPERATING VOLTAGE RATING: PTCs have about twice (sometimes more) D+ D+ IEEE 802.3 XX X D - D - General use PTCs are not rated above 60V the resistance of fuses. IEEE 1394 XXX while fuses are rated up to 600V. I/O Ports XXX X X TIME-CURRENT CHARACTERISTIC: PC Card XXXX XX (2) V0402MHS03 (2) PGB1010603 HOLD CURRENT RATING: The hold Comparing the time-current curves of PTCs ® SCSI XXX X X (PulseGuard (operating) current rating for PTCs can be to time-current curves of fuses show that ESD Suppressor) Video Port XXX X X Signal Signal up to 14A while the maximum level for the speed of response for a PTC is similar LCD Monitor XXXX X Ground Ground Trip Point ® fuses can exceed 30A. to the time delay of a Slo-Blo fuse. Set Top Box XXX X Shield Shield Loudspeaker X Temperature (°C) Ground Ground Smart Card Reader X Mobile Phone XXX Temperature Derating Curves Comparing PTCs to Fuses Understanding the differences in Linear AC/DC Adapter XXXX X X X Chart Key C Portable Electronic Input Port XXXXX performance between the two types of 140 Electromagnetic Loads, Motor XX XX IEEE 1394 – FireWire Tip/Ring circuit – Metallic devices will make the best circuit protection Curve A Solenoid Protection XXXX choice easier. The most obvious difference Thin-Film Fuses and 313 120 A XXXXX Lithium Cell Series (.010 to .150A) is that the PTC is resettable. This is an 1394 Port 1394 Controller RJ11 Connector Tx/Rx Circuits B XXXXX V33MLA1206 inherent characteristic in which the PTC Battery Pack 100 Curve B B ® ® resets (returns to low resistance state) VBU FLAT-PAK , Telelink , 1812L110/33 2® ® after power is removed and the device Nano , PICO , TPA+ Tip 80 Voltage / Current Input Terminal XX TPA- Blade Terminal, cools down. There are a number of other A TPB+ Special Purpose and 600R Series SMD/leaded operating characteristics that differentiate 60 TPB- ® 250R Series SIDACtor other leaded and NOTE: The application summary is for reference only. Determination of suitability for a specific application is the responsibility of the customer. the two types of products. Device cartridge fuses 25°C 40 (except 313.010 – .150A) C Ring The terminology used for PTCs is often (4) PGB1010603 Signal Signal Curve C similar but not the same as for fuses. Two 20 ® Ground Ground (PulseGuard Resettable PTCs parameters that fall into this category are ESD Suppressor) -60°C -40°C -20°C 0°C 20°C 40°C 60°C 80°C 100°C 120°C Shield leakage current and fault current rating. -76°F -40°F -4°F 32°F 68°F 104°F 140°F 176°F 212°F 248°F Ground AMBIENT TEMPERATURE 2 3 4 Log resistance (ohms) PERCENT OF RATING Medical Consumer Battery Computer Telecom electronic Electronics Outside World Outside World Telco Outside World Cell Phone LEAKAGE CURRENT: A PTC is said to TEMPERATURE DERATING: The useful When to apply a resettable PTC vs. a Systems Interface) Standard for this large Littelfuse offers a full range of battery required. The following are typical examples complete protection for the circuit. Contact PTC Characteristics PTC Applications ® have “tripped” when it has transitioned upper limit for a PTC is generally 85°C while traditional fuse is always the choice of the market includes a statement that “....a strap, surface mount and radial leaded of circuits using POLYFUSE resettable your location Littelfuse application expert and Terminology PTCs are used as circuit protection in from its low resistance state to a high the maximum operating temperature for designer or technician but in some cases, Positive Temperature Coeffi cient device resettable PTC devices designed to protect PTCs in combination with other Littelfuse for additional design assistance or applications where sensitive components resistance state due to overload current. fuses is 125°C. The following temperature PTC’s offer a convenient form of circuit must be used instead of a fuse, to limit the applications where overcurrent protection is circuit protection devices to provide visit www.littelfuse.com/PTCs. A polymeric PTC (positive temperature are at risk of damage from overcurrent derating curves (see chart at bottom of protection to improve the reliability of an maximum amount of current sourced”. coeffi cient) overcurrent protector is an Protection is accomplished by limiting the conditions. The ability of PTCs to reset page) that compare PTCs to fuses illustrate application. There is an important area of element placed in series with the circuit or current fl ow to a low leakage level. Leakage The application selection guide below should themselves after exposure to a fault current that more derating is required for a PTC at a applications where the use of resettable assembly to be protected. The PTC current can range from less than a hundred be used as an aid in selecting the proper Power Over Ethernet Li-ion Battery Pack makes them ideal for use in circuits that are given temperature. fuses (PTCs) has become a requirement. element protects the circuit by changing milliamps at rated voltage up to a few device for your end application. Please not easily accessible to a user or technician. Much of the design work for personal Swtich/Hub Powered End Station from a low-resistance to a high resistance hundred milliamps at lower voltages. Additional operating characteristics can be consult the datasheets on www.littelfuse.com Typical applications include port protection Battery Connector Battery Controller IC computers and peripheral devices is state in response to an overcurrent. The fuse on the other hand completely reviewed by the circuit designer in making for detailed technical specifi cations. on personal computers (USB, Firewire, strongly infl uenced by the Microsoft and Data Pair Data Pair interrupts the current fl ow and this open the decision to choose a PTC or a fuse for keyboard/mouse, and serial ports), Battery + This function is called “tripping” of the Intel System Design Guide which states circuit results in no leakage current after it overcurrent protection. Battery - peripherals (hard drives, video cards, and overcurrent protection device. that “Using a fuse that must be replaced has been subjected to an overload current. Control hubs), cell phone, battery packs, industrial each time an overcurrent condition occurs is AGENCY APPROVALS: PTCs are Overcurrent circuit protection can be controls, lighting ballast and motor controls. unacceptable.” And the SCSI (Small Computer Power Source Powered FAULT CURRENT: The PTC is rated for Recognized under the Component accomplished with the use of either a Equipment Device a maximum short circuit current at rated Program of Underwriters Laboratories to (3) V5.5MLA0402 (PSE) (PD) traditional fuse or the more recently SURFACE MOUNT RADIAL LEADED BATTERY STRAP (AXIAL LEADED) (Multilayer voltage. This fault current level is the UL Standard 1434 for Thermistors. developed resettable PTC. Both devices Varistor) Series Name 0805L 1206L 1210L 1812L 2016L 2920L USBR 30R 60R 250R 600R ST LT LR VT VL Signal maximum current that the device can safely The devices have also been approved for function by reacting to the heat generated Ground Application limit keeping in mind that the PTC will not use in Canada by Underwriters Laboratories. by the excessive current fl ow in the circuit. Ul60950 ,TIA-968-A, GR-1089 Requirements XX Data Pair Data Pair Shield actually interrupt the current fl ow (see Approvals for fuses include Recognition The fuse element melts open, interrupting ITU-T Recoomendations XX Ground LEAKAGE CURRENT above). The typical under the Component Program of the current fl ow, while the PTC changes CPE (Customer Premises Equipment) XX short circuit rating of a board-mounted PTC Underwriters Laboratories and the CSA Analog Line Card XX from low resistance to high resistance is 40A; for battery strap PTCs, this value can Component Acceptance Program. In addition, T1/E1/J1 And HDSL XX to limit current fl ow. The graph below reach 100A. Fuses do in fact interrupt the many fuses are listed in accordance with ISDN XX shows the response of the PTC device USB 1.1 USB 2.0 ADSL XX current fl ow in response to the overload and UL/CSA/ANCE (Mexico) 248-14, to temperature. Cable Telephony XX the range of interrupting ratings vary from Supplemental Fuses. PBX/KTS And Key Telephone System XX USB Port USB Controller USB Port USB Controller tens of amperes up to 10,000 amperes at CPU XX RESISTANCE: Reviewing product V5.5MLA0603 V5.5MLA0603 V5.5MLA063 rated voltage. USB XXXX X specifi cations indicates that similarly-rated VBU VBUS IEEE1284 Parallel Data Bus XXX X 1206L150 1206L150 OPERATING VOLTAGE RATING: PTCs have about twice (sometimes more) D+ D+ IEEE 802.3 XX X D - D - General use PTCs are not rated above 60V the resistance of fuses. IEEE 1394 XXX while fuses are rated up to 600V. I/O Ports XXX X X TIME-CURRENT CHARACTERISTIC: PC Card XXXX XX (2) V0402MHS03 (2) PGB1010603 HOLD CURRENT RATING: The hold Comparing the time-current curves of PTCs ® SCSI XXX X X (PulseGuard (operating) current rating for PTCs can be to time-current curves of fuses show that ESD Suppressor) Video Port XXX X X Signal Signal up to 14A while the maximum level for the speed of response for a PTC is similar LCD Monitor XXXX X Ground Ground Trip Point ® fuses can exceed 30A. to the time delay of a Slo-Blo fuse. Set Top Box XXX X Shield Shield Loudspeaker X Temperature (°C) Ground Ground Smart Card Reader X Mobile Phone XXX Temperature Derating Curves Comparing PTCs to Fuses Understanding the differences in Linear AC/DC Adapter XXXX X X X Chart Key C Portable Electronic Input Port XXXXX performance between the two types of 140 Electromagnetic Loads, Motor XX XX IEEE 1394 – FireWire Tip/Ring circuit – Metallic devices will make the best circuit protection Curve A Solenoid Protection XXXX choice easier. The most obvious difference Thin-Film Fuses and 313 120 A XXXXX Lithium Cell Series (.010 to .150A) is that the PTC is resettable. This is an 1394 Port 1394 Controller RJ11 Connector Tx/Rx Circuits B XXXXX V33MLA1206 inherent characteristic in which the PTC Battery Pack 100 Curve B B ® ® resets (returns to low resistance state) VBU FLAT-PAK , Telelink , 1812L110/33 2® ® after power is removed and the device Nano , PICO , TPA+ Tip 80 Voltage / Current Input Terminal XX TPA- Blade Terminal, cools down. There are a number of other A TPB+ Special Purpose and 600R Series SMD/leaded operating characteristics that differentiate 60 TPB- ® 250R Series SIDACtor other leaded and NOTE: The application summary is for reference only. Determination of suitability for a specific application is the responsibility of the customer. the two types of products. Device cartridge fuses 25°C 40 (except 313.010 – .150A) C Ring The terminology used for PTCs is often (4) PGB1010603 Signal Signal Curve C similar but not the same as for fuses. Two 20 ® Ground Ground (PulseGuard Resettable PTCs parameters that fall into this category are ESD Suppressor) -60°C -40°C -20°C 0°C 20°C 40°C 60°C 80°C 100°C 120°C Shield leakage current and fault current rating. -76°F -40°F -4°F 32°F 68°F 104°F 140°F 176°F 212°F 248°F Ground AMBIENT TEMPERATURE 2 3 4 Log resistance (ohms) PERCENT OF RATING Medical Consumer Battery Computer Telecom electronic Electronics Outside World Outside World Telco Outside World Cell Phone that the circuit parameters do not exceed 5. Check that the trip time protects Selection Process these ratings. the circuit. 1. Determine the following circuit operating 4. Verify that the ambient operating 6. Verify that the post trip resistance (R1 ) MAX parameters: temperature within close proximity to of the device is taken into account in the  Normal operating current – I HOLD the device is within its normal operating circuit design.  Maximum circuit voltage – V MAX ® POLYFUSE PTC SELECTION GUIDE  Maximum interrupt current – I MAX range. Thermally derate I and I as HOLD MAX 7. Independently test and evaluate the  Ambient operating temperature necessary. See equation below. suitability and performance of the PTC 2. Select the suitable form factor. in the actual application. I World Headquarters 3. Compare the PTC data sheet ratings on MAX I = HOLD littelfuse.com for V and I to ensure Thermal derating factor Littelfuse, Inc. MAX MAX 800 E. Northwest Highway Des Plaines, IL 60016 USA PTC Selection Table www.littelfuse.com SURFACE MOUNT RADIAL LEADED Series Name 0805L 1206L 1210L 1812L 2016L 2920L USBR 30R International Sales, Asia/PaciŢ c Research and Distribution and Manufacturing Facilities:  Hong Kong, China Photos Engineering Facilities: Phone: +852 2810 5099  Arcola, Illinois USA Fax: +852 2810 5500  Des Plaines, Illinois USA North America Chip Size 0805 (2012) 1206 (3216) 1210 (3225) 1812 (4532) 2016 (5041) 2920 (7351)  Dongguan, China  Birmingham, Michigan USA  Beijing, China Hold Current (I ) 0.10-1.00A 0.125-2.00A 0.05-1.75A 0.10-2.60A 0.3-2.00A 0.30-3.00A 0.75-2.5A 0.9-9.00A HOLD Des Plaines, Illinois USA Phone: +86 10 8454 9408  Dundalk, Ireland Max voltage (V ) 15V 30V 30V 60V 60V 60V 16V 30V MAX and Irving, Texas USA Fax: +86 10 8454 9409  Dünsen, Germany Max fault current (I ) 40A 100A 100A 100A 40A 40A 40A 40A MAX Technical Assistance  Irving, Texas USA  Shanghai, China Operating Temperature Range -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C Phone: 800 999 9445  Lipa City, Philippines Phone: +86 21 5383 8016 Agency approval cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV 847 824 1188 Fax: +86 21 5383 7476  Matamoros, Mexico Fax: 847 391 0459 RoHS Compliant Yes Yes Yes Yes Yes Yes Yes Yes  Piedras Negras, Mexico  Shenzhen, China Lead-Free Yes Yes Yes Yes Yes Yes Yes Yes Europe  Suzhou, China Phone: +86 755 8207 0760 COMPETITOR CROSS Surface Mount  Dünsen, Germany  Swindon, England Fax: +86 755 8207 0759 Tyco/Raychem Series nano SMD micro SMD mini SMD mid SMD SMD RUSB RUE Phone: +49 4244 8190  Witten, Germany Amp Rating NA 0.500-1.50A 0.050-1.50A 0.140-2.60A 0.300-2.00A 0.300-3.00A 0.750-2.50A 0.900-9.00A Fax: +49 4244 819 139  Singapore Battery Strap  Wuxi, China Max voltage NA 6V 6-30V 6-60V 6-60V 6-60V 16V 30V Phone: +65 6885 9111  Munich, Germany  Yangmei, Taiwan Fax: +65 6885 9113 Bourns Series MF-NSMF MF-USMD MF-MSMD MF-SMDF MF-SM MF-R Radial Leaded Phone: +49 8955 27660 Amp Rating NA 0.12-2.00 0.05-1.50A 0.05-1.50A 0.55-2.00A 0.300-2.5A NA 0.90-9.0A  Yokohama, Japan Fax: +49 8955 276 699 High Voltage Max voltage NA 6-30V 6-30V 6-30V 10-60V 6-60V NA 30V Phone: +81 45 478 1088  Utrecht, The Netherlands Radial Leaded NO = Not offered Fax: +81 45 478 1089 Phone: +31 30 299 9900 Fax: +31 30 299 9800  Seoul, Korea PTC Selection Table (cont.) Phone: +82 2 6000 8600  Swindon, England BATTERY STRAP (AXIAL LEADED) Fax: +82 2 6000 8655 Phone: +44 1793 720770 Series Name 60R 250R 600R ST LT LR VT VL  Taipei, Taiwan Fax: +44 1793 720771 Phone: +886 2 8751 1234 Fax: +886 2 8751 1177 Photos Central and South America  São Paulo, Brasil Chip Size Phone: +55 113 835 3780 Hold Current (I ) 0.1-3.75A 0.08-0.18A 0.15-0.16A 1.2-4.2A 0.7-3.4A 1.9-10.00A 1.7-2.4A 1.7-2.3A HOLD Fax: +55 113 645 0612 Max voltage (V ) 60V 60/250V 60/600V 15/24V 15/24V 15/20V 16V 12V MAX Max fault current (I ) 40A 3/10A 3/2.2A 100A 100A 100A 100A 100A MAX Operating Temperature Range -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C -40°C to 85°C Agency approval cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV cULus, TUV RoHS Compliant Yes Yes Yes Yes Yes Yes Yes Yes Lead-Free Yes Yes Yes Yes Yes Yes Yes Yes COMPETITOR CROSS Tyco/Raychem Series RXE TR250 TR600 SRP LTP LR4 VTP VLR Amp Rating 0.100-3.75A 0.080-0.180A 0.150-0.160A 1.20-4.20A 0.700-3.40A 1.7-13A 1.10-2.40A 2.10-2.30A Max voltage 60-72V 60/250V 60/600V 15/30V 24V 15/20V 16V 16V Bourns Series MF-R/MF-RX MF-R/250 MF-R/600 MF-S MF-LS MF-LR MF-VS FORM NO. EC327-E © November 2006, Littelfuse Inc. Printed in U.S.A. Amp Rating 0.10-3.75A 0.08-0.18A 0.15-0.16A 1.2-4.2A 0.70-3.4A 1.9-9.0A 1.7-2.4A NA Specifications, descriptions and illustrative material in this literature are as accurate as known at the time of Max voltage 60V 60/250V 60/600V 15-30V 15-24V 15-20V 16V NA publication, but are subject to change without notice. NA = Not Available 5