VISHAY DALE www.vishay.com Power Metal Strip® Resistors Technical Note WSHM / WSH Side by Side Comparison for a Drop-In Replacement Part By Bryan Yarborough The WSHM is a new addition to the high-power Power Metal Strip® resistor family. The WSHM is a drop-in replacement for the WSH, with higher power handling, tighter tolerance, and a cost advantage over the WSH. We encourage all customers to migrate from the WSH to the WSHM. The below table provides a point-by-point comparison of the two resistors’ datasheet specifications. Datasheet links WSHM2818 WSH2818 Yes Yes < 20 ppm/°C < 20 ppm/°C < 5 nH < 5 nH < 3 μV/°C < 3 μV/°C Yes Yes Size 2818 2818 Power rating 7W 5W 0.5 % tolerance 0.010 to 0.1 - 1.0 % tolerance 0.001 to 0.1 0.001 to 0.1 167.8 mg 126 mg 0.001 to 0.00599 200 ppm/°C 200 ppm/°C 0.006 to 0.1 75 ppm/°C 75 ppm/°C -65 °C to +170 °C -65 °C to +170 °C FEATURES All welded construction Resistor element TCR Very low inductance Low thermal EMF AEC-Q200 qualified STANDARD ELECTRICAL SPECIFICATIONS Resistance range TECHNICAL SPECIFICATIONS Temperature coefficient Operating temperature range Revision: 20-Jul-15 Document Number: 30305 1 For technical questions, contact: [email protected] THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000 TECHNICAL NOTE Weight Technical Note www.vishay.com Vishay Dale WSHM / WSH Side by Side Comparison for a Drop-In Replacement Part Datasheet links WSH2818 WSHM2818 DIMENSIONS in inches (millimeters) L H a T W l b a L 0.28 (7.10) 0.28 (7.10) W 0.18 (4.60) 0.18 (4.60) 0.006 to 0.1 0.059 (1.50) 0.032 (0.813) 0.001 to 0.00599 0.059 (1.50) 0.045 (1.143) T 0.125 (3.18) 0.125 (3.18) a 0.138 (3.50) 0.138 (3.50) b 0.20 (5.10) 0.20 (5.10) l 0.024 (0.61) 0.024 (0.61) H PERFORMANCE Thermal shock LIMITS ± 0.5 % ±1% ±1% Low temperature operation ± 0.5 % ± 0.5 % High temperature exposure ±1% ±1% Bias humidity ± 0.5 % ± 0.5 % Mechanical shock ± 0.5 % ± 0.5 % Vibration ± 0.5 % ± 0.5 % Load life ±1% ±1% Resistance to solder heat ± 0.5 % ± 0.5 % Moisture resistance ± 0.5 % ± 0.5 % Short time overload Revision: 20-Jul-15 Document Number: 30305 2 For technical questions, contact: [email protected] THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000 TECHNICAL NOTE ± 0.5 %