The RSKM3637 is a current-sensing resistor built with a 4-terminal Kelvin sampling arrangement, separating the current-carrying path (I1, I2) from the voltage-sensing connections (U1, U2) to support accurate current measurement. The resistive element, in manganese copper, Karma or Fe-Cr-Al alloy, is joined to red copper terminals by vacuum electron-beam welding in a full-metal structure. The red copper terminals carry a nickel and tin plating, the resistance value is applied by silk-screen marking, and the assembly is coated with a heat-resistant epoxy resin that gives the part excellent weather resistance. The RSKM3637 carries ultra-low thermal EMF and ultra-low parasitic inductance, giving it a fast response suited to high-frequency AC current detection as well as general DC current sensing, along with high reliability, stability and superb pulse load capability.
The RSKM3637 is offered in five value and material combinations under a maximum rated power of 5W. In manganese copper, values of 0.2mΩ, 0.3mΩ and 1mΩ each carry a temperature coefficient of resistance of ±75ppm/°C. In Karma, values from 2mΩ to 30mΩ carry a temperature coefficient of resistance of ±25ppm/°C. In Fe-Cr-Al, values from 1mΩ to 30mΩ carry a temperature coefficient of resistance of ±50ppm/°C. Tolerance is available in ±0.5%, ±1% or ±5% across the range, and all variants share a parasitic inductance of 0.5nH to 5nH, a thermal EMF of less than 1μV/°C over 0-100°C, and an operating temperature range of -55°C to +170°C. Rated power follows a derating curve that holds 100% of rated power up to 70°C ambient before linearly reducing to zero at 170°C.
Physically, the RSKM3637 measures 9.1±0.25mm in length, 9.4±0.25mm in width and 0.8±0.25mm in thickness across all resistance values, with a terminal dimension B of 1.6±0.25mm and C of 0.82±0.25mm. Terminal dimension A varies by value, at 3.5±0.25mm for 0.2mΩ, 3.2±0.25mm for 0.3mΩ, and 2.4±0.25mm for 1mΩ and for the 2-30mΩ and 1-30mΩ ranges. The part is qualified to IEC60115-1 test methods covering temperature coefficient of resistance, solderability, short-time overload, resistance to soldering heat, base plate bending, flammability, insulation resistance, withstand voltage, solvent resistance, high-temperature and humidity exposure, high-temperature storage, low-temperature load, temperature cycling and load life, and is AEC-Q200 qualified and RoHS compliant. Parts are supplied on 13-inch reels for 16mm tape, in quantities of 4,000 pieces per reel.
