Low Value 3W Chip Resistors Welwyn Components LRF3W Series • • • 3 Watts @ 70°C Resistance range from 0.003 to 0.1Ω Tolerances to ±1% Electrical Data Value Power dissipation @70°C Resistance Range 100 % Of Power Rating Characteristic Power Derating Curve 3 Watts 0.005 to 0.100Ω Dielectric withstand 200V Ambient temp range -55 to +150°C Resistance tolerance ≤R005 5%, >R005 2, 5%, ≥R01 1, 2, 5% TCR 60 40 20 0 ±100ppm/°C Pad & trace area for maximum power rating* 80 25° 70° Temperature in °C 150° 300mm2 Physical Data Top Bottom (Board Side) Recommended Solder Pad Layout 0.81 ± 0.13mm 0.51 ± 0.13mm Plating wrap-around 2.29 ± 0.13mm 7.6mm 6.35 ± 0.13mm 2mm 1mm 0.94 mm max thickness 3.18 ± 0.13mm Weight 0.065g typ. General Note Welwyn Components reserves the right to make changes in product specification without notice or liability. All information is subject to Welwyn’s own data and is considered accurate at time of going to print. A subsidiary of TT electronics plc © Welwyn Components Limited · Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: [email protected] · Website: www.welwyn-tt.com 84 Issue D · 07.06 Low Value 3W Chip Resistors Welwyn Components LRF3W Series Chips can withstand immersion in solder at 250°C for 90 seconds and are suitable for reflow or wave soldering mounting applications. Construction Patented non-noble copper based thick film material, overglaze and organic protection are screen printed on a 96% alumina substrate. The components are laser trimmed to achieve the required resistance tolerance. Marking The body protection and marking are resistant to all normal industrial cleaning solvents suitable for printed circuits. Chips are packed and mounted with marking side up. The LRF3W Chips are mounted with the actual resistor element mounted face down on its termination pads. Terminations The wrap-around terminations have an electroplated nickel barrier and matte tin finish, this ensures excellent ‘leach’ resistance properties and solderability. Performance Data Typical Load at rated power: 1000 hours at 70°C MIL-PRF-55342 ∆R% 1 Overload: 6.25 x rated power for 2 seconds MIL-PRF-55342 ∆R% 0.5 High temperature exposure: MIL-PRF-55342 ∆R% 0.5 Low temperature operation: MIL-PRF-55342 ∆R% 0.5 Low temperature storage: -65°C, 100 hours ∆R% 0.5 Moisture: MIL-PRF-55342 ∆R% 0.5 Temperature cycling: MIL-STD-883 Method 1010 Test condition B ∆R% 0.25 Thermal shock: MIL-STD-202 Method 107 condition B -65°C +125°C ∆R% 0.25 Resistance to solder heat: MIL-STD-202 Method 210 ∆R% 0.25 Shelf life test: 12 months at room temperature ∆R% 0.1 Leach resistance: molten solder 250°C 90 Seconds min. Packaging LRF3W Resistors are supplied taped and reeled as per IEC 286-3. The standard quantity per reel is 1800 parts. T2 P0 D0 T 13 ± 0.5mm 33 ± 1.0 G B0 80 ± 2 178 ± 2 F 13 ± 0.5 W E Marking (Both sides) P2 T1 0.8 ± 0.15 2.5 ± 0.5 A0 K0 D1 P1 Tape dimensions in mm LRF3W W ±0.3 12 P1 ±0.1 8 P0 ±0.1 4 P2 ±0.05 2 D0 ±0.1 1.5 D1 ±0.2 1.5 E ±0.1 1.75 F ±0.05 5.5 A0 ±0.1 3.61 B0 ±0.1 6.96 © Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: [email protected] · Website: www.welwyn-tt.com K0 ±0.1 1.17 T ±0.05 0.28 T1 nom 0.06 T2 ±0.15 1.45 Issue D · 07.06 85 Low Value 3W Chip Resistors Welwyn Components LRF3W Series Ordering Procedure Specify type reference, value and tolerance as shown in this example of LRF3W 5mΩ 2%: Type LRF3W R005 G Resistance value (IEC62 code) Tolerance (IEC62 code) F 1% G 2% J 5% © Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: [email protected] · Website: www.welwyn-tt.com 86 Issue D · 07.06