The WSH2818, a 5-watt Power Metal Strip® resistor, is one of the industry's first such devices to offer 5-watt capability in the small 2818 package size. The surface-mount Power Metal Strip resistor, in a package measuring 0.280 in. by 0.180 in. by 0.032 in. [7.1 mm by 4.6 mm by 0.813 mm], also features very low resistance values ranging from 1 milliohm to 100 milliohms.
Designed for use in current sensing, voltage division, and pulse applications; the WSH2818 resistor is intended for use in dc-to-dc conversion and VRMs in desktop and notebook computers; electronic controls in automotive systems, base station power supplies in telecom systems, lithium-ion battery protection and battery charging systems in notebook computers and consumer electronics, and motor controls for industrial systems.
The Vishay Dale WSH2818 resistor features a proprietary construction with improved thermal management to enable a 5-watt power rating in a small package size that maintains the superior electrical performance of the Power Metal Strip construction. As a result, designers are able to incorporate the WSH2818 resistor in place of larger surface-mount components to realize significant board-space savings and enable manufacture of smaller, lighter end products. Alternatively, the designer can use one WSH2818 resistor as a space- and cost-conserving replacement for multiple discrete resistors featuring lower power ratings.
The device's surface-mount construction enhances flexibility in the design of smaller and more robust electronics. For example, the WSH2818 resistor can be used as a 5-watt alternative to a though-hole current-sensing resistor, reducing manufacturing and placement costs by allowing for total solder reflow board assembly and eliminating the need for secondary lead forming and trimming operations.
In addition to a power rating of 5 watts, the Vishay Dale WSH2818 offers low inductance values (<5 nH), excellent frequency response, and low thermal EMF. Rated for an operating temperature range of -65°C to +170°C, the WSH2818 is capable of higher temperature performance than devices built with thin film or thick film resistor technologies. The new device is RoHS compliant and lead (Pb)-free, featuring terminals with a 100% matte tin (Sn) finish over a nickel (Ni) barrier. The WSH2818's all welded metal construction includes a low TCR (<20ppm/°C) nickel-chrome or manganese-copper alloy resistive element.
