PTC thermistors for overcurrent protection Leaded disks, coated, 12 V, 24 V Series/Type: B599*5 Date: June 2011 © EPCOS AG 2011. Reproduction, publication and dissemination of this publication, enclosures hereto and the information contained therein without EPCOS' prior express consent is prohibited. Overcurrent protection Leaded disks, coated, 12 V, 24 V C935 ... C995 Applications Overcurrent protection Short circuit protection Dimensional drawing Features Lead-free terminals Manufacturer's logo and type designation stamped on in white Low resistance For rated currents of up to 1.8 A UL approval to UL 1434 for Vmax = 15 V and VR = 12 V (file number E69802) RoHS-compatible Options Leadless disks and leaded disks without coating available on request Thermistors with diameter w ≤11.0 mm are also available on tape (to IEC 60286-2) Delivery mode Cardboard strips (standard) Cardboard tape reeled or in Ammo pack on request Dimensions (mm) Type C935 C945 C955 C965 C975 C985 C995 wmax 22.0 17.5 13.5 11.0 9.0 6.5 4.0 ∅d 0.6 0.6 0.6 0.6 0.6 0.6 0.5 hmax 25.5 21.0 17.0 14.5 12.5 10.0 7.5 General technical data Max. operating voltage Rated voltage Switching cycles Reference temperature Tolerance of RR Operating temperature range Operating temperature range Please read Cautions and warnings and Important notes at the end of this document. (TA = 60 °C) (typ.) (V = 0) (V = Vmax) Page 2 of 10 Vmax VR N Tref ∆RR Top Top 30 12, 24 100 120 ±25 40/+125 40/+85 V DC or V AC V DC or V AC °C % °C °C Overcurrent protection Leaded disks, coated, 12 V, 24 V C935 ... C995 Electrical specifications and ordering codes Type C935 C945 C955 C965 C975 C985 C995 IR IS ISmax (V = Vmax) mA mA A 1800 1300 850 600 450 250 120 3600 10.0 2600 8.0 1700 5.5 1200 4.3 900 3.0 500 1.0 240 0.7 Ir (typ.) (V = Vmax) mA RR Rmin Ω Ω 170 115 80 70 60 45 25 0.3 0.45 0.8 1.2 1.8 4.6 13 0.2 0.3 0.5 0.7 1.1 2.7 7.8 Approvals Ordering code X X X X X X X B59935C0120A070 B59945C0120A070 B59955C0120A070 B59965C0120A070 B59975C0120A070 B59985C0120A070 B59995C0120A070 Reliability data Test Electrical endurance, cycling Electrical endurance, constant Damp heat Standard IEC 60738-1 Rapid change of temperature IEC 60738-1 Vibration IEC 60738-1 Shock IEC 60738-1 Climatic sequence IEC 60738-1 IEC 60738-1 IEC 60738-1 Please read Cautions and warnings and Important notes at the end of this document. Test conditions Room temperature, ISmax; Vmax Number of cycles: 100 Storage at Vmax /Top,max (Vmax) Test duration: 1000 h Temperature of air: 40 °C Relative humidity of air: 93% Duration: 56 days Test according to IEC 60068-2-78 T1 = Top,min (0 V), T2 = Top,max (0 V) Number of cycles: 5 Test duration: 30 min Test according to IEC 60068-2-14, Test Na Frequency range: 10 to 55 Hz Displacement amplitude: 0.75 mm Test duration: 3 × 2 h Test according to IEC 60068-2-6, Test Fc Acceleration: 390 m/s2 Pulse duration: 6 ms; 6 × 4000 pulses Dry heat: T = Top,max (0 V) Test duration: 16 h Damp heat first cycle Cold: T = Top,min (0 V) Test duration: 2 h Damp heat 5 cycles Tests performed according to IEC 60068-2-30 Page 3 of 10 ∆R25/R25 < 25% < 25% < 10% < 10% < 5% < 5% < 10% Overcurrent protection Leaded disks, coated, 12 V, 24 V C935 ... C995 Characteristics (typical) PTC resistance RPTC versus PTC temperature TPTC (measured at low signal voltage) PTC current IPTC versus PTC voltage VPTC (measured at 25 °C in still air) Switching time tS versus switching current IS (measured at 25 °C in still air) Rated current IR versus ambient temperature TA (measured in still air) Please read Cautions and warnings and Important notes at the end of this document. Page 4 of 10 Overcurrent protection Leaded disks, coated, 12 V, 24 V C935 ... C995 Characteristics (typical) PTC resistance RPTC versus PTC temperature TPTC (measured at low signal voltage) PTC current IPTC versus PTC voltage VPTC (measured at 25 °C in still air) Switching time tS versus switching current IS (measured at 25 °C in still air) Rated current IR versus ambient temperature TA (measured in still air) Please read Cautions and warnings and Important notes at the end of this document. Page 5 of 10 Overcurrent protection Leaded disks, coated, 12 V, 24 V C935 ... C995 Cautions and warnings General EPCOS thermistors are designed for specific applications and should not be used for purposes not identified in our specifications, application notes and data books unless otherwise agreed with EPCOS during the design-in-phase. Ensure suitability of thermistor through reliability testing during the design-in phase. The thermistors should be evaluated taking into consideration worst-case conditions. Storage Store thermistors only in original packaging. Do not open the package before storage. Storage conditions in original packaging: storage temperature 25 °C ... +45 °C, relative humidity ≤75% annual mean, maximum 95%, dew precipitation is inadmissible. Avoid contamination of thermistors surface during storage, handling and processing. Avoid storage of thermistor in harmful environment with effect on function on long-term operation (examples given under operation precautions). Use thermistor within the following period after delivery: Through-hole devices (housed and leaded PTCs): 24 months Motor protection sensors, glass-encapsulated sensors and probe assemblies: 24 months Telecom pair and quattro protectors (TPP, TQP): 24 months Leadless PTC thermistors for pressure contacting: 12 months Leadless PTC thermistors for soldering: 6 months SMDs in EIA sizes 3225 and 4032, and for PTCs with metal tags: 24 months SMDs in EIA sizes 0402, 0603, 0805 and 1210: 12 months Handling PTCs must not be dropped. Chip-offs must not be caused during handling of PTCs. Components must not be touched with bare hands. Gloves are recommended. Avoid contamination of thermistor surface during handling. Soldering (where applicable) Use rosin-type flux or non-activated flux. Insufficient preheating may cause ceramic cracks. Rapid cooling by dipping in solvent is not recommended. Complete removal of flux is recommended. Standard PTC heaters are not suitable for soldering. Please read Cautions and warnings and Important notes at the end of this document. Page 6 of 10 Overcurrent protection Leaded disks, coated, 12 V, 24 V C935 ... C995 Mounting Electrode must not be scratched before/during/after the mounting process. Contacts and housing used for assembly with thermistor have to be clean before mounting. Especially grease or oil must be removed. When PTC thermistors are encapsulated with sealing material, the precautions given in chapter "Mounting instructions", "Sealing and potting" must be observed. When the thermistor is mounted, there must not be any foreign body between the electrode of the thermistor and the clamping contact. The minimum force of the clamping contacts pressing against the PTC must be 10 N. During operation, the thermistor’s surface temperature can be very high. Ensure that adjacent components are placed at a sufficient distance from the thermistor to allow for proper cooling at the thermistors. Ensure that adjacent materials are designed for operation at temperatures comparable to the surface temperature of thermistor. Be sure that surrounding parts and materials can withstand this temperature. Avoid contamination of thermistor surface during processing. Operation Use thermistors only within the specified temperature operating range. Use thermistors only within the specified voltage and current ranges. Environmental conditions must not harm the thermistors. Use thermistors only in normal atmospheric conditions. Avoid use in deoxidizing gases (chlorine gas, hydrogen sulfide gas, ammonia gas, sulfuric acid gas etc), corrosive agents, humid or salty conditions. Contact with any liquids and solvents should be prevented. Be sure to provide an appropriate fail-safe function to prevent secondary product damage caused by abnormal function (e.g. use VDR for limitation of overvoltage condition). Please read Cautions and warnings and Important notes at the end of this document. Page 7 of 10 Overcurrent protection Leaded disks, coated, 12 V, 24 V C935 ... C995 Symbols and terms A Cth f I Imax IR IPTC Ir Ir,oil Ir,air IRMS IS ISmax LCT N Nc Nf P P25 Pel Pdiss RG Rmin RR ∆RR RP RPTC Rref RS R25 R25,match ∆R25 T t TA ta TC Area Heat capacity Frequency Current Maximum current Rated current PTC current Residual currrent Residual currrent in oil (for level sensors) Residual currrent in air (for level sensors) Root-mean-square value of current Switching current Maximum switching current Lower category temperature Number (integer) Operating cycles at Vmax, charging of capacitor Switching cycles at Vmax, failure mode Power Maximum power at 25 °C Electrical power Dissipation power Generator internal resistance Minimum resistance Rated resistance Tolerance of RR Parallel resistance PTC resistance Reference resistance Series resistance Resistance at 25 °C Resistance matching per reel/ packing unit at 25 °C Tolerance of R25 Temperature Time Ambient temperature Thermal threshold time Ferroelectric Curie temperature Please read Cautions and warnings and Important notes at the end of this document. Page 8 of 10 Overcurrent protection Leaded disks, coated, 12 V, 24 V C935 ... C995 tE TR Tsense Top TPTC tR Tref TRmin tS Tsurf UCT V or Vel VRMS VBD Vins Vlink,max Vmax Vmax,dyn Vmeas Vmeas,max VR VPTC Settling time (for level sensors) Rated temperature Sensing temperature Operating temperature PTC temperature Response time Reference temperature Temperature at minimum resistance Switching time Surface temperature Upper category temperature Voltage (with subscript only for distinction from volume) Root-mean-square value of voltage Breakdown voltage Insulation test voltage Maximum link voltage Maximum operating voltage Maximum dynamic (short-time) operating voltage Measuring voltage Maximum measuring voltage Rated voltage Voltage drop across a PTC thermistor α ∆ δth τth λ Temperature coefficient Tolerance, change Dissipation factor Thermal cooling time constant Failure rate Lead spacing (in mm) Abbreviations / Notes Surface-mount devices * To be replaced by a number in ordering codes, type designations etc. + To be replaced by a letter All dimensions are given in mm. The commas used in numerical values denote decimal points. Please read Cautions and warnings and Important notes at the end of this document. Page 9 of 10 Important notes The following applies to all products named in this publication: 1. Some parts of this publication contain statements about the suitability of our products for certain areas of application. These statements are based on our knowledge of typical requirements that are often placed on our products in the areas of application concerned. We nevertheless expressly point out that such statements cannot be regarded as binding statements about the suitability of our products for a particular customer application. As a rule, EPCOS is either unfamiliar with individual customer applications or less familiar with them than the customers themselves. For these reasons, it is always ultimately incumbent on the customer to check and decide whether an EPCOS product with the properties described in the product specification is suitable for use in a particular customer application. 2. We also point out that in individual cases, a malfunction of electronic components or failure before the end of their usual service life cannot be completely ruled out in the current state of the art, even if they are operated as specified. In customer applications requiring a very high level of operational safety and especially in customer applications in which the malfunction or failure of an electronic component could endanger human life or health (e.g. in accident prevention or lifesaving systems), it must therefore be ensured by means of suitable design of the customer application or other action taken by the customer (e.g. installation of protective circuitry or redundancy) that no injury or damage is sustained by third parties in the event of malfunction or failure of an electronic component. 3. The warnings, cautions and product-specific notes must be observed. 4. In order to satisfy certain technical requirements, some of the products described in this publication may contain substances subject to restrictions in certain jurisdictions (e.g. because they are classed as hazardous). Useful information on this will be found in our Material Data Sheets on the Internet (www.epcos.com/material). Should you have any more detailed questions, please contact our sales offices. 5. We constantly strive to improve our products. Consequently, the products described in this publication may change from time to time. The same is true of the corresponding product specifications. Please check therefore to what extent product descriptions and specifications contained in this publication are still applicable before or when you place an order. We also reserve the right to discontinue production and delivery of products. Consequently, we cannot guarantee that all products named in this publication will always be available. The aforementioned does not apply in the case of individual agreements deviating from the foregoing for customer-specific products. 6. Unless otherwise agreed in individual contracts, all orders are subject to the current version of the "General Terms of Delivery for Products and Services in the Electrical Industry" published by the German Electrical and Electronics Industry Association (ZVEI). 7. The trade names EPCOS, BAOKE, Alu-X, CeraDiode, CSMP, CSSP, CTVS, DeltaCap, DigiSiMic, DSSP, FormFit, MiniBlue, MiniCell, MKK, MKD, MLSC, MotorCap, PCC, PhaseCap, PhaseCube, PhaseMod, PhiCap, SIFERRIT, SIFI, SIKOREL, SilverCap, SIMDAD, SiMic, SIMID, SineFormer, SIOV, SIP5D, SIP5K, ThermoFuse, WindCap are trademarks registered or pending in Europe and in other countries. Further information will be found on the Internet at www.epcos.com/trademarks. Page 10 of 10