Resistors Moulded Surface Mount Moulded Surface Mount Wirewound Resistors Wirewound Resistors Welwyn Components WSM Series WSM Series * Ideal for automatic pick and place * Direct Flexiblereplacement Terminations for Axial resistors All welded construction welded construction * All Ideal for automatic pick and place Lead free, RoHS compliant construction only Contact factory for ohmic values above published ranges All parts are Pb-free and comply with EU Directive 2011/65/EU amended by (EU) 2015/863 (RoHS3) Electrical Data WSM1 Power rating at 70C watts Resistance range ohms Limiting element voltage WSM2 1 2 3 0R01 to 400R 0R01 to 1K 0R05 to 3K < 1 : 100 < 1 : 100 volts TCR 100 ppm/C 1 : 20 Resistance tolerance WSM3 1 : 20 % .03 700 0.1 : 200 10R 100 >10R 20 *1, 2, 5, 10 Standard values E24 preferred Ambient temperature range C -55 to 275C *Note 1% and 5% preferred. WSM1 available at 5% only below 1R0. WSM2 available at 5% only below 0R05. Physical Data Dimensions Inches (mm) Type L max I Nom A Max W Max H Max WSM1 0.310 max (7.9 max) 0.462 max (11.7 max) 0.275 max (7.0 max) 0.425 max (10.8 max) 0.165 max (4.2 max) WSM2 0.115 max (2.9 max) 0.137 max (3.5 max) 0.260 max (6.6 max) 0.155 max (3.94 max) 0.195 max (5.0 max) WSM3 0.677 max (17.2 max) 0.137 max (3.5 max) 0.64 max (16.3 max) 0.29 max (7.4 max) 0.265 inch (6.7 max) L A W I H Recommended Pad Sizes B C WSM1 0.13 inch (3.3 mm) A 0.138 inch (3.5 mm) 0.074 inch (1.9 mm) 0.35 inches (8.9 mm) WSM2 0.157 inch (4.0 mm) 0.181 inch (4.6 mm) 0.221 inch (5.6 mm) 0.583 inch (14.8 mm) WSM3 0.157 inch (4.0 mm) 0.236 inch (6.2 mm) 0.378 inch (9.6 mm) 0.85 inch (21.6 mm) Type D Construction A high purity ceramic substrate is assembled with interference fit end caps to which are welded the terminations. The resistive element is wound on the substrate and welded to the caps. The unit is then moulded. Flammability The resistor coating is a flame retardant epoxy to UL 94. B C A D Marking WSM resistors are legend marked with type value and tolerance. WSM1 Resistors are marked with value and tolerance. Solvent Resistance The body protection and marking are resistant to all normal industrial cleaning solvents suitable for printed circuits. General Note Welwyn Components reserves the right to make changes in product specification without notice or liability. General Noteis subject to Welwyn's own data and is considered accurate at time of going to print. All information subsidiary of BI Technologies IRC A Welwyn TT Electronics reserves the right to make changes in product specification without notice or liability. Bedlington, Northumberland UK to print. (c)information WelwynisComponents Limited All subject to TT Electronics' own *data and is considered accurate NE22 at time7AA, of going Telephone: +44 (0) 1670 822181 * Facsimile: +44 (0) 1670 829465 * Email: info@welwyn-tt.com * Website: www.welwyn-tt.com TT electronics plc www.ttelectronics.com/resistors Issue C * 04.03 (c) TT Electronics plc 06.18 45 Moulded Surface MountMount Moulded Surface Wirewound Resistors Wirewound Resistors Welwyn Components WSM Series WSM Series Packing Data Dimensions (mm) Ao Bo Ko W P t WSM1 4.2 7.62 4.2 16 8 0.36 WSM2 6.75 11.95 5.22 24 12 0.36 WSM3 7.3 18.3 6.7 32 12 0.4 All other dimensions as per EIA481 standard Performance Data WSM1 WSM2 WSM3 Load at rated power: 1000 hrs @ 70C R% 2 0.001 2 0.001 3 0.001 Dry heat R% 2 0.001 2 0.001 3 0.001 1000 hrs @ 155C R% Short term overload 2 0.001 Derating from rated power @ 70C zero at 275C Moisture R% Temperature cycling R% 1 0.001 Resistance to solder heat R% 1 0.001 Isolation voltage 1 0.001 1 0.001 V 1.5 0.001 1,000 Insulation resistance ohms >1000M Substrate bend R% 0.2 0.001 Note: The power ratings to be applied depend upon the board used and the ambient temperature. Ordering Procedure Example: WSM2 at 4.7 ohms and 5% tolerance on a reel of 800 pieces - WSM2- 4R7JI Type Value (use IEC62 code) Tolerance (use IEC62 code) F G 1% 2% J K Packing I Tape 5% 10% WSM1 WSM2 WSM3 1500/reel 800/reel 750/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. BI Technologies IRC Welwyn (c) Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 (c) TT Electronics plc 822181 * Facsimile: +44 (0) 1670 829465 * Email: info@welwyn-tt.com * Website: www.welwyn-tt.com 46 www.ttelectronics.com/resistors Issue C * 04.02 06.18 Moulded Surface Mount Wirewound Resistors WSM Series Ordering Procedure This product has two valid part numbers: European (Welwyn) Part Number: WSM3-6K8FI (WSM3, 6.8 kilohms 1%, Pb-free) W S M 3 - 6 K 1 8 2 1 2 Type Value F I 3 4 3 4 Tolerance Packing & Termination Finish WSM1 E24 = 3/4 characters WSM2 R = ohms K = kilohms WSM3 F = 1% G = 2% J = 5% K = 10% I = Standard packing & Pb-free WSM1 1500/reel (13" 330mm) WSM2 800/reel (13" 330mm) WSM3 750/reel (13" 330mm) USA (IRC) Part Number: WSM36801FLFTR (WSM3, 6.8 kilohms 1%, Pb-free) W S M 3 6 8 1 0 2 1 2 Type Value 1 F 3 WSM1 3 digits + multiplier WSM2 R = ohms for values <100 ohms WSM3 L F T 4 R 5 3 4 Tolerance Termination Finish F = 1% G = 2% J = 5% K = 10% LF = Pb-free 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. 5 Packing TR = Tape & Reel WSM1 1500/reel (13" 330mm) WSM2 800/reel (13" 330mm) WSM3 750/reel (13" 330mm) BI Technologies IRC Welwyn www.ttelectronics.com/resistors (c) TT Electronics plc 06.18