RTO 50 Vishay Sfernice Power Resistor, Thick Film Technology FEATURES • 50 Watt at 25°C Heatsink Mounted • Adjusted by sand trimming • Leaded or surface mount versions • High power to size ratio • Non inductive element Because of the knowledge and experience in Thick Film technology, Vishay Sfernice has been able to develop a high power resistor in a TO 220 package called RTO 50. The special design of this component allows the dissipation of 50W when mounted on a heatsink. The ohmic value is adjusted by sand trimming. This process does not generate hot spots as in laser trimming, which could lead to microcracks on each side of the curve. This process improves the reliability and the stability of the resistor and at the same time gives a good overload capability. DIMENSIONS in millimeters RTO 50F - LEADED RTO 50C - FOR SURFACE MOUNTING 4.5 10.1 Ø 3.6 12.5 4.5 1.3 10.1 Ø 3.6 15 8.8 12.5 1.3 15 8.8 2 3 13.7 0.3 1.8 5.08 Ø 0.8 2.5 5.08 • Tolerance unless otherwise specified: ± 0.4mm MECHANICAL SPECIFICATIONS ELECTRICAL SPECIFICATIONS Mechanical Protection Molded Resistance Range 0.010Ω to 1MΩ Resistive Element Thick Film Tolerances Standard ± 1% to ± 10% Connections Tinned copper alloy Dissipation and Associated Onto a heatsink Weight 2g max. Thermal Resistance 50W at + 25°C RTH (j-c): 2.6°C/W free air: 2.25W at + 25°C and Nominal Power DIMENSIONS Standard Package TO 220 Insulated Case ENVIRONMENTAL SPECIFICATIONS Temperature Range - 55°C to + 155°C Climatic Category 55/155/156 Sealing Sealed container Solder immersion Temperature Coefficient Standard Limiting Element Voltage Dielectric Strength ± 150ppm/°C 300V 2000VRMS - 1 Minute - 10mA Max MIL STD 202 (301) Insulation Resistance ≥ 106 MΩ Inductance ≤ 0.1 µH Critical Resistance Document Number: 50035 Revision 14-Jan-05 See Performance table For technical questions, contact [email protected] 1.8 kΩ www.vishay.com 17 RTO 50 Vishay Sfernice Power Resistor Thick Film Technology PERFORMANCE TESTS CONDITIONS TYPICAL DRIFTS NF EN 140000 2Pr/5s ± (0.25% + 0.05Ω) NF EN 140000 CEI 68214 Tests Na ± (0.5% + 0.05Ω) NF EN 140000 Pr at + 25°C CEI 115_1 ± (1% + 0.05Ω) Humidity (Steady State) Method 103 B Cond. D MIL STD 202 ± (0.5% + 0.05Ω) Vibration Method 204 Cond. D MIL STD 202 ± (0.2% + 0.05Ω) Terminal Strength Method 211 Cond. A1 MIL STD 202 ± (0.2% + 0.05Ω) Momentary Overload Us < 1.5UL Rapid Temperature Change 5 cycles - 55°C to + 155°C Load Life SPECIAL FEATURES Resistance Values ≥ 0.010Ω ≥ 0.015Ω ≥ 0.1Ω Tolerances Temperature Coefficient ≥ 0.5Ω ± 1% at ± 10% Standard ± 900ppm/°C ± 700ppm/°C ± 250ppm/°C ± 150ppm/°C CHOICE OF THE HEATSINK The user must choose according to the working conditions of the component (power, room temperature). Maximum working temperature must not exceed 155°C. The dissipated power is simply calculated by the following ratio: P= ∆T (1) [RTH (j-c) + RTH (c-a)] P: expressed in W T: difference between maximum working temperature and room temperature. RTH: (j-c): thermal resistance value measured between resistive layer and outer side of the resistor. It is the thermal resistance of the component: (Special Features Table) RTH: (c-a): thermal resistance value measured between outer side of the resistor and room temperature. It is the thermal resistance of the heatsink itself (type, shape) and the quality of the fastening device. Example: RTH: (c-a) for RTO 50 power rating 13 W at ambient temperature + 30°C. Thermal resistance RTH (j-c): 25°C/W Considering equation (1) we have: ∆T ≤ 155°C - 30°C ≤ 125°C 125 ∆T RTH (j-c) + RTH (c-a) = = = 9.6°C/W 13 P RTH (c-a) ≤ 9.6°C/W - 2.6°C/W ≤ 7°C/W www.vishay.com 18 For technical questions, contact [email protected] Document Number: 50035 Revision 14-Jan-05 RTO 50 Power Resistor Thick Film Technology Vishay Sfernice OVERLOADS The applied voltage must always be lower than the maximum overload voltage of 450V. The values indicated on the graph below are applicable to resistors in air or mounted onto a heatsink. ENERGY CURVE ENERGY IN JOULES 10 1 0.1 0.01 10-6 10-5 10-4 10-3 10-2 OVERLOAD DURATION IN SECONDS POWER RATING CHART The temperature of the heatsink should be maintained within the limits specified. To improve the thermal conductivity, surfaces in contact should be coated with a silicone grease and the torque applied on the screw for tightening should be around 1Nm. % RATED POWER 100 75 50 25 0 0 25 40 60 80 100 120 140 155 HEATSINK TEMPERATURE IN DEGREES CELSIUS MARKING Model, Style, Resistance Value (in ), Tolerance (in %), Manufacturing Date, VISHAY trademark. PACKAGING Tube of 50 units ORDERING INFORMATION RTO MODEL 50 STYLE F CONNECTIONS F: Leaded C: Surface Mount Document Number: 50035 Revision 14-Jan-05 100 k� RESISTANCE VALUE ± 1% TOLERANCE xxx CUSTOM DESIGN ± 1% ± 2% ± 5% ± 10% Optional on request: special TCR, shap, etc. For technical questions, contact [email protected] www.vishay.com 19 Legal Disclaimer Notice Vishay Notice Specifications of the products displayed herein are subject to change without notice. Vishay Intertechnology, Inc., or anyone on its behalf, assumes no responsibility or liability for any errors or inaccuracies. Information contained herein is intended to provide a product description only. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Vishay's terms and conditions of sale for such products, Vishay assumes no liability whatsoever, and disclaims any express or implied warranty, relating to sale and/or use of Vishay products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright, or other intellectual property right. The products shown herein are not designed for use in medical, life-saving, or life-sustaining applications. Customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Vishay for any damages resulting from such improper use or sale. Document Number: 91000 Revision: 08-Apr-05 www.vishay.com 1