Resistors Moulded Surface Mount Moulded Surface Mount Wirewound Resistors Welwyn Components Wirewound Resistors WSM Series WSM Series Ideal for automatic pick and place Direct replacement for Axial resistors Flexib le Terminations All welded construction All welded construction Ideal for automatic pick and place Lead free, RoHS compliant construction only Contact factor y for ohmic values above published ranges AllAll partsparts araree Pb-Pb-frfreeee andand ccomplyomply withwith EUEU DirDirectivectivee 2011/65/EU2011/65/EU amendedamended bbyy (EU)(EU) 2015/8632015/863 (R(RoHS3)oHS3) Electrical Data WSM1 WSM2 WSM3 Power rating at 70C watts 1 2 3 Resistance range ohms 0R01 to 400R 0R01 to 1K 0R05 to 3K Limiting element voltage volts 100 TCR ppm/C < 1 : 100 < 1 : 100 .03 700 0.1 : 200 1 : 20 1 : 20 10R 100 >10R 20 Resistance tolerance % *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) L Type L max I Nom A Max W Max H Max A W 0.310 max 0.115 max 0.275 max 0.165 max 0.155 max WSM1 (7.9 max) (7.0 max) (4.2 max) (2.9 max) (3.94 max) I H 0.137 max 0.425 max 0.195 max 0.462 max 0.260 max WSM2 (3.5 max) (10.8 max) (5.0 max) (11.7 max) (6.6 max) 0.137 max 0.64 max 0.677 max 0.29 max 0.265 inch WSM3 (3.5 max) (17.2 max) (16.3 max) (7.4 max) (6.7 max) Recommended Pad Sizes Type A B C D 0.13 inch 0.35 inches 0.138 inch 0.074 inch B C WSM1 (3.3 mm) (8.9 mm) (3.5 mm) (1.9 mm) 0.157 inch 0.221 inch 0.583 inch 0.181 inch A WSM2 (4.0 mm) (5.6 mm) (14.8 mm) (4.6 mm) 0.157 inch 0.236 inch D 0.378 inch 0.85 inch WSM3 (4.0 mm) (6.2 mm) (9.6 mm) (21.6 mm) Construction Marking A high purity ceramic substrate is assembled with interference WSM resistors are legend marked with type value and fit end caps to which are welded the terminations. The tolerance. resistive element is wound on the substrate and welded to WSM1 Resistors are marked with value and tolerance. the caps. The unit is then moulded. Solvent Resistance Flammability The body protection and marking are resistant to all normal The resistor coating is a flame retardant epoxy to UL 94. 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 Note All information is subject to Welwyns own data and is considered accurate at time of going to print. A subsidiary of BI Technologies IRC Welwyn TT Electronics reserves the right to make changes in product specification without notice or liability. TT electronics plc Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK All information is subject to TT Electronics own data and is considered accurate at time of going to print. www.ttelectronics.com/resistors Telephone: +44 (0) 1670 822181 Facsimile: +44 (0) 1670 829465 Email: info welwyn-tt.com Website: www.welwyn-tt.com Issue C 04.03 TT Electronics plc 45 06.18t p j K = = OVLQLMP = =NMWPU= ~ = = m~= O Moulded Surface Mount Moulded Surface Mount Wirewound Resistors Wirewound Resistors WSM Series Welwyn Components 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 1000 hrs 155C R% 2 0.001 2 0.001 3 0.001 Short term overload R% 2 0.001 Derating from rated power 70C zero at 275C Moisture R% 1 0.001 1 0.001 1.5 0.001 Temperature cycling R% 1 0.001 Resistance to solder heat R% 1 0.001 Isolation voltage V 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 Proced ure Example: WSM2 at 4.7 ohms and 5% tolerance on a reel of 800 pieces W S M 2 4 R 7 J I Type Value (use IEC62 code) Tolerance (use IEC62 code) F 1% J 5% G 2% K 10% Packing WSM1 1500/reel I Tape WSM2 800/reel Standard WSM3 750/reel General Note BI Technologies IRC Welwyn 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.ttelectronics.com/resistors Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK T TT Electronics plcelephone: +44 (0) 1670 822181 Facsimile: +44 (0) 1670 829465 Email: info welwyn-tt.com Website: www.welwyn-tt.com Issue C 04.02 06.18 46