document number: 50050 for technica l questions, contact: sfer@vishay.com www.vishay.com revision: 16-oct-08 1 lto 50 vishay sfernice power resistor thick film technology 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. feature ? 50 w at 25 c case temperature heatsink mounted ? direct mounting ceramic on heatsink ? broad resistance range: r010 to 550k ? non inductive ? to-220 package: compact and easy to mount ? rohs compliant ? isolated case dimensions in millimeters mechanical specifications mechanical protection molded resistive element thick film substrate alumina connections tinned copper weight 2 g max. mounting torqure 1 nm dimensions standard package to-220 isolated case environmental specifications temperature range - 55 c to + 155 c climatic category 55/155/56 flammability iec 60695-11-5 2 applications 30 s separated by 60 s rohs compliant 3.2 16.2 10.4 1.8 5.08 0.6 3.5 1.3 0.8 12.7 ? 3.2 3.2 electrical specifications resistance range 0.010 to 550 k tolerances (standard) 1 % to 10 % dissipation and associated onto a heatsink power rating and thermal resistance of the component 50 w at + 25 c (case temp.) r th (j - c): 2.5 c/w free air: 2.5 w at + 25 c temperature coefficient see performance table standard 150 ppm/c limiting element voltage u l 250 v dielectric strength mil std 202 1500 v rms - 1 min 10 ma max. insulation resistance 10 4 m inductance 0.1 h critical resistance 1.25 k
www.vishay.com for technical ques tions, contact: sf er@vishay.com document number: 50050 2 revision: 16-oct-08 lto 50 vishay sfernice power resistor thick film technology choice of the heatsink the user must choose according to the working condit ions of the component (power, room temperature). maximum working temperature must not exceed 150 c. the dissi pated power is simply calculated by the following ratio: p: expressed in w t: difference between maximum worki ng temperature and room temperature r th (j - c): thermal resistance value measured between resistiv e layer and outer side of the resistor. it is the thermal resistance of the component. r th (c - a): thermal resistance value measur ed between outer side of the resistor and room temperature. it is the thermal resistance of the heatsink itself (ty pe, shape) and the quality of the fast ening device, and the thermal resistance of the thermal compound. example: r th (c - a) for lto 50 power rating 10 w at ambient temperature + 25 c thermal resistance r th (j - c): 2.5 c/w considering equation (1) we have: t = 150 c - 25 c = 125 c r th (j - c) + r th (c - a) = = = 12.5 c/w r th (c - a) = 12.5 c/w - 2.5 c/w = 10 c/w with a thermal grease r th (c - h) = 1 c/w, we need a heatsink with r th (h - a) = 9 c/w. performance tests conditions requirements momentary overload en 60115-1 1.5 pr/5 s u s < 1.5 u l (0.5 % + 0.005 ) rapid temperature change en 60115-1 iec 60068-2-14 tests na 5 cycles - 55 c to + 155 c (0.5 % + 0.005 ) load life en 60115-1 1000 h pr at + 25 c (1 % + 0.005 ) humidity (steady state) mil std 202 method 103 b cond. d (0.5 % + 0.005 ) vibration mil std 202 method 204 cond. d (0.2 % + 0.005 ) terminal strength mil std 202 method 211 cond. a1 (0.2 % + 0.005 ) shock 100g, mil std 202 method 213 cond. i (0.5 % + 0.005 ) special features resistance values 0.010 0.015 0.1 0.5 tolerances 1 % at 10 % typical temperature coefficient (- 55 to + 155 c) 900 ppm/c 700 ppm/c 250 ppm/c 150 ppm/c p t r th jc ? () r th ca ? () + [] --------------------------------------------------------------------- - 1 () = t p ------- 125 10 --------- -
document number: 50050 for technica l questions, contact: sfer@vishay.com www.vishay.com revision: 16-oct-08 3 lto 50 power resistor thick film technology vishay sfernice overloads in any case the applied voltage must be lower than the maximum overload voltage of 375 v. the values indicated on the graph below are applicable to resistors in air or mounted onto a heatsink. marking model, style, resistance value (in ), tolerance (in %), manufacturing date, vishay trademark. power rating chart the temperature of the case sh ould 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 1 nm. 10 -6 10 -5 10 -4 10 -3 10 -2 energy in joules overload duration in s ener gy curve 0.01 0.1 1 10 packaging tube of 50 units 0 20 40 60 80 100 120 140 150 100 75 50 25 0 % rated power heatsink temperature in c ordering information lto 50 f 2.7 k 1 % xxx tu50 e3 model style connections resistance value tolerance 1 % 2 % 5 % 10 % custom design optional on request: special tcr, shape etc. packaging lead (pb)-free global part number information global model size leads ohmic value tolerance packaging lead (pb)-free lto 050 f = radial leads the firts four digits are significant figures and the last digit specifies the number of zeros to follow. r designates decimal point. 4 8 r70 = 48.7 4 8 701 = 48 700 10002 = 100 000 r0100 = 0.01 r4700 = 0.47 27000 = 2700 = 2k7 f = 1 % g = 2 % j = 5 % k = 10 % t = tube tube 50 pieces e3 = pure tin 050f270 0 t 3 t o l 0je
document number: 91000 www.vishay.com revision: 18-jul-08 1 disclaimer legal disclaimer notice vishay all product specifications and data are subject to change without notice. vishay intertechnology, inc., its affiliates, agents, and employees, and all persons acting on its or their behalf (collectively, ?vishay?), disclaim any and all liability fo r any errors, inaccuracies or incompleteness contained herein or in any other disclosure relating to any product. vishay disclaims any and all li ability arising out of the use or application of any product describ ed herein or of any information provided herein to the maximum extent permit ted by law. the product specifications do not expand or otherwise modify vishay?s terms and conditions of purcha se, including but not limited to the warranty expressed therein, which apply to these products. no license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document or by any conduct of vishay. the products shown herein are not designed for use in medi cal, life-saving, or life-sustaining applications unless otherwise expressly indicated. customers using or selling vishay products not expressly indicated for use in such applications do so entirely at their own risk and agree to fully indemnify vishay for any damages arising or resulting from such use or sale. please contact authorized vishay personnel to obtain written terms and conditions regarding products designed for such applications. product names and markings noted herein may be trademarks of their respective owners.
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