RTOP Vishay Sfernice Power Resistors for Mounting onto a Heatsink Thick Film Technology FEATURES • 1% tolerance available • High power rating • Wide ohmic value range • Non inductive • Easy mounting • Low thermal radiation of the case • Standard Isotop case (SOT 227 B) This series of thick film power resistors include modules which can incorporate up to 2 different resistor values in the same SOT 227B package. Two types of terminations are available along with a 4 terminal device for measurement applications in the case of the single resistor version. This product range benefits from Vishay Sfernice’s experience in thick film power resistor technology i.e high power: volume ratio, low tolerance or individual resistors and excellent overload capabilities (due to the trimming technique). DIMENSIONS in millimeters RTOP V Connections • Tolerances unless otherwise specified: ± 0.3mm MECHANICAL SPECIFICATIONS Mechanical Protection Substrate Resistive Element End Connection Tightening Torque Connections Tightening Torque Heatsink Insulated case Alumina on insulated base Cermet V connections: screw M4 x 6 1 Nm 2 Nm ENVIRONMENTAL SPECIFICATIONS Temperature Range Climatic Category Document Number: 50045 Revision 14-Jan-04 - 55°C to + 125°C 55/125/56 ELECTRICAL SPECIFICATIONS Resistance Range 0.046 to 1MΩ Standard Tolerance ± 1% to ± 10% Power Rating 50W to 200W at + 25°C Temperature Coefficient Standard Insulation Resistance For technical questions, contact [email protected] ± 300 ppm/˚C (R < 1) ± 150 ppm/˚C (R > 1) > 106MΩ www.vishay.com 27 RTOP Vishay Sfernice Power Resistors for Mounting onto a Heatsink Thick Film Technology PERFORMANCE TESTS CONDITIONS TYPICAL DRIFTS NF EN 140000 CEI 115_1 2.5Pn/5 seconds < ± (0.25% + 0.05Ω) NF EN 140000 CEI 68214 Test Na 5 cycles - 55°C +125°C < ± (0.25% + 0.05Ω) NF EN 140000 CEI 115_1 Pn at 25°C 1000 hours < ± (0.5% + 0.05Ω) MIL STD 202 Method 103 B Test D 56 days 95% R.H. < ± (0.5% + 0.05Ω) Momentary Overload Rapid Temperature Change Load Life Humidity (steady state) SPECIAL FEATURES MODEL RTOP 200 RTOP 100 DRTOP 100 DRTOP 50 Power Rating at + 25°C chassis mounted resistors unmounted resistors 200W 5W 100W 5W 100W 3.5W 50W 3.5W Thermal Resistance (per resistor) 0.5°C/W 1°C/W 0.5°C/W 1°C/W 1500V 1500V 500V 500V 2500V, 1 Minute 10mA Max 2500V, 1 Minute 10mA Max 2500V, 1 Minute 10mA Max 2500V, 1 Minute 10mA Max Limiting Voltage Dielectric Strength* connections/chassis 2500V, 1 Minute 10mA Max Dielectric Strength* connections/resistors - 2500V, 1 Minute 10mA Max - Ohmic Value Range 0.046 to 1MΩ 0.092 to 1MΩ Tolerance ± 1% to ± 10% ± 1% to ± 10% Electrical Diagrams R R2 R1 R Shunt Version *MIL STD 202 Method 301 www.vishay.com 28 For technical questions, contact [email protected] Document Number: 50045 Revision 14-Jan-05 RTOP Power Resistors for Mounting onto a Heatsink Thick Film Technology Vishay Sfernice CHOICE OF HEATSINK The user must choose the heatsink according to the working conditions of the component (power, room temperature). Maximum working temperature must not exceed 125°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 (see Table Special Features). RTH: (c-a): thermal resistance value measured between outer side of the resistor and room temperature. It is the thermal resistance of the heatsink depending on the heatsink itself (type, shape) and the quality of the fastening device. Example: RTH: (c-a) for RTOP 200 power rating 130W at ambient temperature + 30°C. Thermal resistance (see table 1) RTH (j-c): 0.5°C/W ∆T ≤ 125°C - 30°C - ≤ 95°C 95 ∆T RTH (j-c) + RTH (c-a) = = = 0.73°C/W P 130 RTH (j-c) ≤ 0.5°C/W RTH (c-a) ≤ 0.73°C/W - 0.5°C/W ≤ 0.23°C/W RECOMMENDATIONS FOR MOUNTING ONTO A HEATSINK Surfaces in contact must be carefully cleaned. The heatsink must have an acceptable flatness: from 0.05mm to 0.1mm/100mm. Roughness of the heater must be around 6.3µm. In order to improve thermal conductivity, surfaces in contact (alumina, heatsink) are laid on with a silicone grease (type SI 340 from Rhône-Poulenc or Dow 340 from Dow Corning). Tightening torque on heater: 2 Nm For the electrical connections, it is recommended to use M4 x 6 screws and if necessary a washer of 1mm thickness. The recommended screw tightening torque is 1 Nm. Document Number: 50045 Revision 14-Jan-04 For technical questions, contact [email protected] www.vishay.com 29 RTOP Vishay Sfernice Power Resistors for Mounting onto a Heatsink Thick Film Technology OVERLOADS The applied power is 2.5 x rated power for 5 s with a max voltage of 2 x nominal voltage. Accidental overload: The values indicated in the graph below are applicable to resistors in air or mounted onto a heatsink. In case of multi-resistor devices, (DRTOP, TROP and QROP) the results apply to each resistor value in the device. ENERGY CURVE 1000 ENERGY IN JOULES 100 10 1 0.1 0.01 1.10-7 1.10-6 1.10-5 1.10-4 1.10-3 1.10-2 1.10-1 1 OVERLOAD DURATION IN SECONDS RTOP DRTOP POWER RATING CHART The temperature of the heater should be maintained in the limit specified. To improve the thermal conductivity, surfaces in contact should be laid on with a silicon grease and the torque applied on the screw for tightening should be around 2 Nm. 100 % RATED POWER 80 60 40 20 0 0 20 40 60 80 100 120 140 HEATSINK TEMPERATURE IN DEGREES CELSIUS MARKING Series, style, ohmic value (in ), tolerance (in %), manufacturing date, VISHAY trade mark. ORDERING INFORMATION RTOP 200 3.2 ± 1% ±% R1 MODEL STYLE RTOP DRTOP 100 50 www.vishay.com 30 OHMIC VALUE T1 R2 ABSOLUTE TOLERANCE PER RESISTOR Optional ± 1% ± 2% ±5% ± 10 % V To be precise for each resistor For technical questions, contact [email protected] CONNECTIONS CUSTOM DESIGN V: Screw VS: RTOP Shunt Optional Document Number: 50045 Revision 14-Jan-05