High Power Chip Resistors Welwyn Components SC3 Series • • • 3 Watts in a 1 Watt size package* Resistance range from 1 to 200 Tolerances to ±1% * Rated Power @ 70˚C Electrical Data Power Derating Curve Value Power dissipation @70˚ C 3 Watts Resistance Range 100 % Of Power Rating Characteristic 1.0 to 200 LEV 50V Ambient temp range -55 to +150˚C Resistance tolerance 1, 2, 5% TCR ±100ppm/˚C Leach-resistant solder-plated copper wrap-around Termination Pad & trace area for maximum power rating 80 60 40 20 0 300mm2 25˚ 70˚ Temperature in ˚C 150˚ Physical Data Top Bottom (Board Side) Recommended Solder Pad Layout 0.61 ± 0.13mm 0.51 ± 0.13mm Plating wrap-around 2.29 ± 0.13mm 7.6mm 6.35 ± 0.13mm 2mm 1mm 3.18 ± 0.13mm 0.762 ± 0.127mm thickness 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. © 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 A subsidiary of TT electronics plc Issue A 03.02 Issue B · 01.07 High Power Chip Resistors Welwyn Components SC3 Series Construction Resistive 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. Terminations The wrap-around terminations have anhave electroplated nickel copper terminations an electroplated barrier and matte tin finish.solder This ensures nickel barrier and tin-lead coating, this ensures excellent ‘leach’ resistance properties and solderability. Chips can withstand immersion in solder at 250˚C for 90 seconds and are suitable for reflow or wave soldering mounting applications. 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 SC3 Chips are mounted with the actual resistor element mounted face down on its termination pads. 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. Temperature Rise vs Pad Area Pulse Power Rating 1000 Power (watts) Temperature Rise (˚C) 100 100 10 10 1 100mm2 300mm2 1000mm2 0.1 Termination Pad Area (each end) 1 watt 2 watt 1.0 10.0 Time (sec) 3 watt © 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 Issue BA ·· 01.07 03.02 Issue 85 High Power Chip Resistors Welwyn Components SC3 Series Packaging LRF3W Resistors supplied taped reeled as per 286-3. standard quantity is 1800 parts. SC3 Resistors areare supplied taped andand reeled as per IECIEC 286-3. TheThe standard quantity perper reelreel is 1800 parts. T2 P0 D0 T 33 ± 1.0 P2 13 ± 0.5mm E Marking (Both sides) W G B0 80 ± 2 178 ± 2 F 13 ± 0.5 T1 0.8 ± 0.15 2.5 ± 0.5 A0 K0 D1 P1 Tape dimensions in mm LRF3W SC3 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 K0 ±0.1 1.17 T ±0.05 0.28 T1 nom 0.06 T2 ±0.15 1.45 Ordering Procedure Specify type reference etc. as shown in this example of SC3 at 33 SC3 Type - 33R 1% F 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 Issue BA ·· 01.07 03.02