WSM SERIES MOLDED SURFACE MOUNT WIREWOUND RESISTOR * * * * * All welded construction Ideal for automatic pick and place Direct replacement for axial resistors Contact factory for ohmic values above published ranges Lead-Free, ROHS Conpliant Construction Available SPECIFICATIONS: Power rating at 70C Resistance range Limiting element voltage TCR Resistance tolerance Standard values Ambient temperature WSM3 WSM2 3 2 0.01 to 3K 0.01 to 2K 100 100 < .03 : 700 < 0.1 : <1 : 100 200 < 1 : 20 *1, 2, 5, 10 E24 preferred -55 to 155 WSM1 1 0.01 to 1K 100 <10 : 100 >10 : 20 watts ohms volts ppm/C % C Recommended Pad Sizes: B *Note: 5% or 10% preferred below 0.1 ohms. 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 molded. C A Flammability: The resistor coating is categorized as flame retardant epoxy under UL-94. Solvent Resistance: The body protection and marking are resistant to all normal industrial cleaning solvents suitable for printed circuits. Marking: WSM resistors are legend marked with type, value and tolerance. D WSM1 WSM2 WSM3 Dimensions: in (mm) in (mm) in (mm) A B C D .115 (2.9) .100 (2.6) .189 (4.8) .389 (9.9) .134 (3.4) .158 (4.0) .237 (6.0) .552 (14.0) .134 (3.4) .178 (4.5) .434 (11.0) .788 (20.0) L L l W l w w W H P/N in WSM-1 (mm) WSM -2 (mm) WSM-3 (mm) General Note in in L .310 max (7.9 max) .473 max (12 max) .709 max (18 max) l .100 nom (2.54 nom) .122 nom (3.1 nom) .122 nom (3.1 nom) H .275 max (7.0 max) .413 max (10.5 max) .630 max (16 max) IRC reserves the right to make changes in product specification without notice or liability. All information is subject to IRC's own data and is considered accurate at time of going to print. W .165 max (4.2 max) .260 max (6.6 max) .276 max (7 max) w .155 max (3.94 max) .217 max (5.5 max) .256 max (6.5 max) Issue Preliminary 1205 WIREWOUND AND FILM TECHNOLOGIES DIVISION 736 Greenway Road * Boone, North Carolina 28607-1860 * Tel: 828-264-8861 * Fax: 828-264-8866 * www.irctt.com A subsidiary of TT electronics plc WSM PERFORMANCE DATA: R% Load at rated power: 1000 hrs. at 70C Dry heat: 1000 hrs. @ 155C R% R% Short term overload Derating from rated power @ 70C R% Moisture R% Temperature cycling R% Resistance to solder heat Isolation voltage V Insulation resistance ohms R% Substrate bend WSM1 2 0.001 2 0.001 1 0.001 WSM2 2 0.001 2 0.001 2 0.001 zero at 155C 1 0.001 1 0.001 1 0.001 1,000 >1000M 0.2 0.001 WSM3 3 0.001 3 0.001 1.5 0.001 Note: The power ratings to be applied depend upon the board used and the ambient temperature. HOW TO ORDER: Specify type, reference, etc. as indicated in this example of a WSM3 6.8K ohms 5% resistor with tape and reel packaging. STANDARD QUANTITIES PER PACKAGE: WSM3 6K8 J R LF Type Code WSM1 WSM2 WSM3 Type 13" Reel (330mm) Value Tolerance (F=1%, G=2%, J=5%, K=10% WS M3 800 750 Packaging: WSM2 resistors are supplied on .945 (24mm) wide carrier tape. WSM3 resistors are supplied on 1.26 (32mm) wide carrier tape. Both products are reeled onto 13.00 (330mm) diameter reels. Lead Free Construction WS M2 1500 *For packaging information, see Appendix "A". Packaging Code WS M1 R Ao Bo Ko W P T .165 .300 .165 .630 .315 .014 (4.2) (7.62) (4.20) (16.0) (8.00) (0.36) .266 .470 .206 .945 .473 .014 (6.75) (11.95) (5.22) (24.0) (12.0) (0.36) .288 .721 .264 1.26 .473 .016 (7.3) (18.3) (6.7) (32.0) (12.0) (0.4) WIREWOUND AND FILM TECHNOLOGIES DIVISION 736 Greenway Road * Boone, North Carolina 28607-1860 * Tel: 828-264-8861 * Fax: 828-264-8866 * www.irctt.com