B57350K0102J000

NTC thermistors for temperature measurement Leadless NTCs Series/Type: Date: B57350K February 2009 © EPCOS AG 2009. Reproduction, publication and dissemination of this publication, enclosures hereto and the information contained therein without EPCOS' prior express consent is prohibited. Temperature measurement and compensation Leadless NTCs B57350K K350 Applications Temperature measurement and compensation Features Front surfaces silver-plated For clamp contacting Options Alternative resistance ratings, rated temperatures and resistance tolerances available on request. Delivery mode Bulk Dimensional drawing ∅d = 3.5 ±0.3 mm th = 1.3 ±0.4 mm Approx. weight 75 mg General technical data Climatic category Max. power Resistance tolerance Rated temperature Dissipation factor Thermal cooling time constant Heat capacity (IEC 60068-1) (at 25 °C) 55/155/21 180 ±5 100 approx. 2.5 approx. 18 approx. 45 (in air) (in air) P25 ∆RR/RR TR δth1) τc1) Cth1) mW % °C mW/K s mJ/K Electrical specification and ordering codes R100 Ω 70 R25 Ω 990.2 No. of R/T characteristic 1009 B25/100 K 3930 ±1.5% Ordering code B57350K0102J000 1) Depends on mounting situation Please read Cautions and warnings and Important notes at the end of this document. Page 2 of 12 Temperature measurement and compensation Leadless NTCs B57350K K350 Reliability data Test Storage in dry heat Standard IEC 60068-2-2 Test conditions ∆R25/R25 (typical) < 3% Remarks No visible damage Storage in damp heat, steady state Rapid temperature cycling Endurance Long-term stability (empirical value) Storage at upper category temperature T: 155 °C t: 1000 h IEC Temperature of air: 40 °C 60068-2-78 Relative humidity of air: 93% Duration: 21 days IEC Lower test temperature: 55 °C 60068-2-14 Upper test temperature: 155 °C Number of cycles: 100 Pmax: 180 mW t: 1000 h Temperature: 125 °C t: 10000 h < 3% No visible damage No visible damage No visible damage No visible damage < 3% < 3% < 5% Please read Cautions and warnings and Important notes at the end of this document. Page 3 of 12 Temperature measurement and compensation Leadless NTCs B57350K K350 R/T characteristics R/T No. 1009 T (°C) B25/100 = 3930 K T (°C) RT/R25 α (%/K) 55.0 50.0 45.0 40.0 35.0 30.0 25.0 20.0 15.0 10.0 5.0 0.0 5.0 10.0 15.0 85.423 60.781 43.65 31.629 23.118 17.04 12.649 9.4864 7.1545 5.4479 4.1732 3.2256 2.5147 1.9763 1.5649 7.0 6.8 6.6 6.4 6.2 6.1 5.9 5.8 5.6 5.4 5.2 5.1 4.9 4.8 4.6 20.0 25.0 30.0 35.0 40.0 45.0 50.0 55.0 60.0 65.0 70.0 75.0 80.0 85.0 90.0 B25/100 = 3930 K T (°C) RT/R25 α (%/K) 1.2481 1.0000 0.80956 0.65726 0.53697 0.44169 0.36534 0.30327 0.25313 0.21271 0.17962 0.15219 0.12949 0.11067 0.094952 4.5 4.3 4.2 4.1 4.0 3.9 3.8 3.7 3.5 3.4 3.4 3.3 3.2 3.1 3.0 95.0 100.0 105.0 110.0 115.0 120.0 125.0 130.0 135.0 140.0 145.0 150.0 155.0 B25/100 = 3930 K RT/R25 α (%/K) 0.08178 0.07069 0.061383 0.053486 0.04673 0.040955 0.036006 0.031747 0.028097 0.024935 0.022176 0.019772 0.017683 3.0 2.9 2.8 2.7 2.7 2.6 2.5 2.5 2.4 2.4 2.3 2.3 2.2 Please read Cautions and warnings and Important notes at the end of this document. Page 4 of 12 Temperature measurement and compensation Leadless NTCs B57350K K350 Mounting instructions 1 1.1 Soldering Leaded NTC thermistors Leaded thermistors comply with the solderability requirements specified by CECC. When soldering, care must be taken that the NTC thermistors are not damaged by excessive heat. The following maximum temperatures, maximum time spans and minimum distances have to be observed: Dip soldering Bath temperature Soldering time Distance from thermistor max. 260 °C max. 4 s min. 6 mm Iron soldering max. 360 °C max. 2 s min. 6 mm Under more severe soldering conditions the resistance may change. 1.2 Leadless NTC thermistors In case of NTC thermistors without leads, soldering is restricted to devices which are provided with a solderable metallization. The temperature shock caused by the application of hot solder may produce fine cracks in the ceramic, resulting in changes in resistance. To prevent leaching of the metallization, solder with silver additives or with a low tin content should be used. In addition, soldering methods should be employed which permit short soldering times. 2 Clamp contacting Pressure contacting by means of clamps is particularly suitable for applications involving frequent switching and high turn-on powers. 3 Robustness of terminations (leaded types) The leads meet the requirements of IEC 60068-2-21. They may not be bent closer than 4 mm from the solder joint on the thermistor body or from the point at which they leave the feedthroughs. During bending, any mechanical stress at the outlet of the leads must be removed. The bending radius should be at least 0.75 mm. Tensile strength: Test Ua1: Leads 0.25 < 0.35 < 0.50 < 0.80 < ∅ ≤0.25 mm = 1.0 N ∅ ≤0.35 mm = 2.5 N ∅ ≤0.50 mm = 5.0 N ∅ ≤0.80 mm = 10.0 N ∅ ≤1.25 mm = 20.0 N Please read Cautions and warnings and Important notes at the end of this document. Page 5 of 12 Temperature measurement and compensation Leadless NTCs B57350K K350 Bending strength: Test Ub: Two 90°-bends in opposite directions at a weight of 0.25 kg. Torsional strength: Test Uc: severity 2 The lead is bent by 90° at a distance of 6 to 6.5 mm from the thermistor body. The bending radius of the leads should be approx. 0.75 mm. Two torsions of 180° each (severity 2). When subjecting leads to mechanical stress, the following should be observed: Tensile stress on leads During mounting and operation tensile forces on the leads are to be avoided. Bending of leads Bending of the leads directly on the thermistor body is not permissible. A lead may be bent at a minimum distance of twice the wire's diameter +2 mm from the solder joint on the thermistor body. During bending the wire must be mechanically relieved at its outlet. The bending radius should be at least 0.75 mm. Twisting of leads The twisting (torsion) by 180° of a lead bent by 90° is permissible at 6 mm from the bottom of the thermistor body. 4 Sealing and potting When thermistors are sealed, potted or overmolded, there must be no mechanical stress caused by thermal expansion during the production process (curing / overmolding process) and during later operation. The upper category temperature of the thermistor must not be exceeded. Ensure that the materials used (sealing / potting compound and plastic material) are chemically neutral. 5 Cleaning If cleaning is necessary, mild cleaning agents such as ethyl alcohol and cleaning gasoline are recommended. Cleaning agents based on water are not allowed. Ultrasonic cleaning methods are permissible. 6 Storage In order to maintain their solderability, thermistors must be stored in a non-corrosive atmosphere. Humidity, temperature and container materials are critical factors. Do not store SMDs where they are exposed to heat or direct sunlight. Otherwise, the packing material may be deformed or SMDs may stick together, causing problems during mounting. After opening the factory seals, such as polyvinyl-sealed packages, use the SMDs as soon as possible. Please read Cautions and warnings and Important notes at the end of this document. Page 6 of 12 Temperature measurement and compensation Leadless NTCs B57350K K350 The components should be left in the original packing. Touching the metallization of unsoldered thermistors may change their soldering properties. Storage temperature: Relative humidity (without condensation): 25 °C up to 45 °C ≤75% annual mean