333 3 LTO 50 www.vishay.com Vishay Sfernice Power Resistor Thick Film Technology FEATURES 50 W at 25 C case temperature heatsink mounted Direct mounting ceramic on heatsink Broad resistance range: 0.010 to 550 k Non inductive TO-220 package: compact and easy to mount Material categorization: for definitions of compliance please see www.vishay.com/doc 99912 LINKS TO ADDITIONAL RESOURCES 3D Models LTO series are the extension of RTO types. We used the direct ceramic mounting design (no metal tab) of our RCH power resistors applied to semiconductor packages. DIMENSIONS in millimeters 3.2 10.4 3.2 16.2 3.2 1.3 3.5 12.7 0.8 0.6 1.8 5.08 Note Tolerances unless stated: 0.3 mm STANDARD ELECTRICAL SPECIFICATIONS RESISTANCE RATED POWER LIMITING ELEMENT TEMPERATURE CRITICAL TOLERANCE MODEL SIZE RANGE P VOLTAGE U COEFFICIENT RESISTANCE 25 C L % W V ppm/C LTO 50 TO-220 0.010 to 550K 50 500 1, 2, 5, 10 150, 250, 700, 900 5K MECHANICAL SPECIFICATIONS TECHNICAL SPECIFICATIONS Mechanical Protection Molded Dissipation and Associated Onto a heatsink Resistive Element Thick film 50 W at +25 C (case temp.) Power Rating and Substrate Alumina R : 2.5 C/W TH (j - c) Thermal Resistance Connections Tinned copper Free air: of the Component 2.5 W at +25 C Weight 2 g max. Mounting Torque 1 Nm Temperature Coefficient See Performance table Standard 150 ppm/C ENVIRONMENTAL SPECIFICATIONS Dielectric Strength 1500 V - 1 min RMS Temperature Range -55 C to +150 C MIL STD 202 10 mA max. Climatic Category 55 / 155 / 56 4 Insulation Resistance 10 M IEC 60695-11-5 Flammability 2 applications 30 s Inductance 0.1 H separated by 60 s Revision: 25-Nov-2020 Document Number: 50050 1 For technical questions, contact: sferfixedresistors vishay.com THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc 91000 DDD D LTO 50 www.vishay.com Vishay Sfernice PERFORMANCE TESTS CONDITIONS REQUIREMENTS EN 60115-1 Momentary Overload 1.5 Pr / 5 s (0.5 % + 0.005 ) U < 1.5 U S L EN 60115-1 IEC 60068-2-14 Test Na Rapid Temperature Change (0.5 % + 0.005 ) 5 cycles -55 C to +155 C EN 60115-1 Load Life (1 % + 0.005 ) 1000 h Pr at +25 C MIL-STD-202 Humidity (Steady State) (0.5 % + 0.005 ) method 103 B cond. D MIL-STD-202 Vibration (0.2 % + 0.005 ) method 204 cond. D MIL-STD-202 Terminal Strength (0.2 % + 0.005 ) method 211 cond. A1 100G, MIL-STD-202 Shock (0.5 % + 0.005 ) method 213 cond. I SPECIAL FEATURES Resistance Values 0.010 0.015 0.1 0.5 Tolerances 1 % at 10 % Typical Temperature Coefficient 900 ppm/C 700 ppm/C 250 ppm/C 150 ppm/C (-55 to +155 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 150 C. The dissipated power is simply calculated by the following ratio: ()1 T P = ------------------------------------------------------------------------------------------- R ++R R TH (j - c) TH (c - h) TH (h - a) P: Expressed in W R : Thermal resistance value measured between outer side of TH (c - h) T: Difference between maximum working temperature and roo m the resistor and upper side of the heatsink. This is the therma l temperature resistance of the interface (grease, thermal pad), and the quality of R : Thermal resistance value measured between resistive laye r the fastening device. TH (j - c) and outer side of the resistor. It is the thermal resistance of the R : Thermal resistance of the heatsink. TH (h - a) component. Example: R for LTO 50 power rating 10 W at ambient temperature +25 C TH (c - a) Thermal resistance R : 2.5 C/W TH (j - c) (1) Considering equation we have: T = 150 C - 25 C = 125 C T 125 R + R + R = ------ = -------- = 12.5 C/W TH (j - c) TH (c - h) TH (h - a) P 10 R + R = 12.5 C/W - 2.5 C/W = 10 C/W TH (c - h) TH (h - a) with a thermal grease R = 1 C/W, we need a heatsink with R = 9 C/W. TH (c - h) TH (h - a) Revision: 25-Nov-2020 Document Number: 50050 2 For technical questions, contact: sferfixedresistors vishay.com THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc 91000