power resistors thick film technology www.vishay.com for technical questions, contact: sfer@vishay.com document number: 50005 14 revision: 05-jun-07 rto 20 vishay sfernice the well known to 220 package is compact and easy to mount. features ? 20 w at 25 c heatsink mounted ? high power dissipati on to size ratio ? wide resistance range from 0.01 to 1 m ? negligible inductance ? easy mounting ? to 220 package: compact and easy to mount two versions of this thick film resistor are available: ? a radial leaded version for pcb mounting ? a flat lead version for surface mounting dimensions in millimeters mechanical specifications mechanical protection insulated case resistive element thick film connections tinned copper weight 2.2 g max. dimensions standard package to 220 insulated case environmental specifications temperature range - 55 c to + 155 c climatic category 55/155/56 sealing sealed container solder immersion flammability iec 60695-11-5 2 applications 30 s seperated by 60 s rohs compliant ? tolerance unless otherwise specified: 0.4 mm rto 20f - leaded 4.5 1.3 8.8 ? 0.8 10.1 13.7 12.5 5.08 15 ? 3.6 2.5 rto 20c - for surface mounting 4.5 1.3 8.8 10.1 12.5 5.08 15 ? 3.6 0.3 1.6 3 2 ? only for rto 20 version c = durin g surface mount solderin g temperature profile must not cause the metal tab of this device to exceed 220 c. electrical specifications resistance range 0.010 to 1 m serie e24 tolerances (standard) 1 % to 10 % dissipation and associated: onto a heatsink thermal resistance and nominal power 20 w at + 25 c r th (j-c): 6.5 c/w free air: 2 w at + 25 c temperature coefficient see performance table standard (- 55 c; + 150 c) 150 ppm/c limiting element voltage 250 v dielectric strength mil std 202 2000 v rms - 1 min - 10 ma max (between terminals and heatsink) insulation resistance 10 6 m inductance 0.1 h critical resistance 3.12 k
rto 20 power resistors thick film technology vishay sfernice document number: 50005 for technica l questions, contact: sfer@vishay.com www.vishay.com revision: 05-jun-07 15 note: for very low ohmic values, tcr for information choice of the heatsink the user must choose according to the working condi tions of the component ( power, room temperature). maximum working temperature must not exceed 155 c. the di ssipated 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: (special features table) r th : (c-a): thermal resistance value measured between outer side of the resistor and room temp erature. it is the thermal resistance of the heatsink itself (type, sha pe) and the quality of the fastening device. example: r th : (c-a) for rto 20 power rating 10 w at ambient temperature + 25 c thermal resistance r th (j-c): 6.5 c/w considering equation (1) we have: performance tests conditions typical drifts momentary overload en 60115-1 2 pr for r < 2 1.6 pr for r 2 us < 1.5 ul (0.25 % + 0.005 ) rapid temperature change en 60115-1/60068-2-14 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) en 60115-1 56 days r.h. 95 % (0.5 % + 0.005 ) high temperature exposure nf en 140 000 1000 h - 40 % pr at + 100 c (0.5 % + 0.005 ) vibration mil std 202, method 204 c test d (0.2 % + 0.005 ) terminal strength mil std 202, method 211 test a1 (0.2 % + 0.005 ) shock iec 60115-1 iec 60068-2-27 saw tooth: 100 g/6 ms (0.5 % + 0.005 ) special features resistance values 0.01 0.015 0.1 0.5 tolerances 1 % at 10 % typical temperature coefficient range (- 55 c/+ 155 c) 900 ppm/c 700 ppm/c 250 ppm/c 150 ppm/c p = t r th (j-c) + r th (c-a) [] ------------------------------------------------------------ - 1 () t 155 c - 25 c 130 c == r th (j-c) + r th (c-a) = t p ------- = 130 10 --------- - = 13 c/w r th (c-a) = 13 c/w - 6.5 c/w = 6.5 c/w
www.vishay.com for technical questions, contact: sfer@vishay.com document number: 50005 16 revision: 05-jun-07 rto 20 vishay sfernice power resistors thi ck film technology overloads in any case the applied voltage must be lowe r 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. 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 1 nm. spring clip can also be used to mount the component on an heatsink (ex: kunze, clip ku4-498). marking model, style, resistance value (in ), tolerance (in %), manufacturing date, vishay trademark. packaging tube of 50 units ordering information rto 20 f u6 8 5 % xxx tu50 e3 model style connections resistance value to lerance custom design packaging lead (pb)-free f: radial leads c: surface mount 1 % 2 % 5 % 10 % optional on request: special tcr, shape etc. sap part numbering guidelines rto 020 f r6 8 00 j t e3 model style connections resistance va lue tolerance packaging lead (pb)-free 10 -6 energy in joules overload duration in seconds energy curve 0.01 0.1 1 10 10 -5 10 -4 10 -3 10 -2 10 -1 10 -7 100 0 100 75 50 25 0 % rated power heatsink temperature in c 20 40 60 80 100 120 140 155 120
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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