Low Resistance Metal Low Resistance Metal Resistance Metal Element Resistors Element Resistors Element Resistors Welwyn Components Welwyn Components LOB Series LOB Series LOB Series * Ultra low resistance values Ultra low resistance values * Ultra low resistance values (0.005 (0.005 to 0.1)to 0.1) (0.005 to 0.1) 1, 35and watt rated packages * Available Available in 1, 3inand watt5 rated packages in 1, 3 and 5 watt rated packages * Available Tolerances from from 1% to 5% Tolerances 1% to 5% * * * * from non-inductive 1% to 5% ** Tolerances Inherently non-inductive (.02H at 0.5MHz) (.02H at 0.5MHz) * Inherently ** Inherently Low temperature coefficient of resistance non-inductive (.02H at 0.5MHz) * Low temperature coefficient of resistance ** Low Hightemperature stability over life over life of resistance * High stabilitycoefficient * High stability over life Electrical Data Electrical Data LOB-1 watts LOB-1 Continuous power dissipation at 25C in free air Continuous powerpower dissipation at 25C in free air Overload for 5 seconds watts watts OverloadMaximum power forworking 5 seconds voltage watts volts Maximum workingstorage voltage temperature Maximum volts C LOB-3 LOB-5 1 LOB-3 3 LOB-5 1 5 3 15 5 25 5 1xR 15 3xR 25 5xR 175 3xR 175 5xR 175 1xR 5 Maximum storage temperature Cof heat which 175 175 175 * Power Dissipation - The maximum wattage rating depends upon the amount can be transferred to the surroundings while not exceeding the maximum element temperature. Ambient air temperature, velocity of cooling air, thermal resistance of heat and the temperature of surrounding objects will affect this transfer, this must be taken * Power Dissipation - The maximum wattage rating depends upon the amount of heat which can be transferred to the surroundings while not exceeding the maximum element into account when selecting a resistor. temperature. Ambient air temperature, velocity of cooling air, thermal resistance of heat and the temperature of surrounding objects will affect this transfer, this must be taken into account when selecting a resistor. Physical Data Physical Data Dimensions (mm) Dimensions (mm) Type L max. Type contact point D max. f min. d nom. L max. 9.90.3 D max. 3.60.2 f min. 38.13.2 d nom. C LOB-1 0.8130.05 C contact point LOB-3 14.220.25 5.330.25 34.933.18 0.810.05 33.27 42.42 LOB-5 23.370.25 8.380.25 31.753.18 1.020.05 LOB-5 23.370.25 8.380.25 31.753.18 1.020.05 d d contact point C 33.27 LOB-1 LOB-3 9.90.3 3.60.25.330.25 38.13.2 0.8130.05 33.27 33.27 14.220.25 34.933.18 0.810.05 contact point C D D L L f f 42.42 Description Construction LOB Series power precision metal element resistors feature LOB Series resistors feature tinned copper leads welded Description Construction resistance values downmetal to 0.005 with virtually no directly to a low temperature coefficient LOB Series power precision element resistors feature LOB Series resistors feature tinned copper leadsresistance welded element in inductance. Available in 1, 3with andvirtually 5 watt rated proprietary Theelement leaded resistor resistance values down to 0.005 no axial leaded directly atohighly a lowautomated temperature coefficientprocess. resistance in packages, these compatible withleaded automatic a highlyelements are proprietary then encapsulated a moulding compound. inductance. Available in resistors 1, 3 andare 5 watt rated axial automated process.inThe leaded resistor insertion packages, these equipment. resistors are compatible with automatic elements are then encapsulated in a moulding compound. insertion equipment. Applications Applications * Switchmode and linear power supplies. * * * Switchmode and linear power supplies. current-sensing circuits. * Automotive Automotive current-sensing circuits. Instrumentation. * Instrumentation. General Note Welwyn Components reserves the right to make changes in product specification without notice or liability. A subsidiary of Welwyn Components reserves the right to make changes in product specification without notice or liability. TT electronics plc TT electronics reserves the right to make changes in product specification without notice or liability. A subsidiary of All information is subject to Welwyn's own data and is considered accurate at time of going to print. (c) Welwyn Components Limited * Bedlington, Northumberland NE22 7AA, to UKprint. All information is subject to TT electronics' own data and is considered accurate at time of going TT electronics plc www.bitechnologies.com Issue B * 03.02 Telephone: +44 (0) 1670 822181 * Facsimile: +44 (0) 1670 829465 * Email: info@welwyn-tt.com * Website: www.welwyn-tt.com www.irctt.com www.welwyn-tt.com (c) Welwyn Components Limited * Bedlington, Northumberland NE22 7AA, UK Issue B * 03.02 Telephone: +44 (0) 1670 (c) TT electronics plc822181 * Facsimile: +44 (0) 1670 829465 * Email: info@welwyn-tt.com * Website: www.welwyn-tt.com GeneralAll Note General Note information is subject to Welwyn's own data and is considered accurate at time of going to print. 104 104 11. 11 LowResistance Resistance Low MetalMetal Element Resistors Element Resistors Welwyn Components LOB LOB Series Series Power derating percentage vs Free air ambient temperature Temperature coefficient of resistance vs Resistance value Temperature Coefficient of resistance (ppm/C) 100 Rated Power (%) 90 80 70 60 50 40 30 20 10 0 0 25 50 75 100 125 150 175 400 300 200 100 0 0 25 50 Resistance (ohms x Ambient Temp (C) 75 100 10-3) Test MIL-STD 202 MAX % R* Unit Load life (2000 hours) Method 108 1% %R Thermal shock Method 107 1% %R Vibration Method 204 0.5% %R %R Mechanical shock Method 213 0.5% Dielectric strength Method 301 0.5% %R Insulation resistance Method 302 >1011 ohms *0.0005 ohm allowance for test/contact error. Packaging Resistors are supplied taped and reeled. Bulk packaging available. Ordering Procedure Example: LOB3 at 10 milliohms and 5% tolerance on a reel of 1250 pieces LOB3- R01JI Type Value (use IEC62 code) Tolerance (use IEC62 code) F H 1% 3% J 5% Note: 1% & 5% preferred Packing I Tape LOB1 LOB3 LOB5 3500/reel 1250/reel 800/reel Standard General Note TT electronics reserves the right to make changes in product specification without notice or liability. All information is subject to TT electronics' own data and is considered accurate at time of going to print. www.bitechnologies.com www.irctt.com www.welwyn-tt.com (c) Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK Issue B * 03.02 Telephone: +44 (0) 1670 (c) TT electronics plc822181 * Facsimile: +44 (0) 1670 829465 * Email: info@welwyn-tt.com * Website: www.welwyn-tt.com 11. 11 105