Vishay’s New WSH2818 5-Watt Surface-Mount Power Metal Strip Resistor may be First Such Device in Compact 2818 Package Size

February 15, 2006 by Jeff Shepard

Vishay Intertechnology Inc. has announced a new 5-watt Power Metal Strip® resistor that could be the industry's first such device to offer 5-watt capability in the small 2818 package size, company officials said. The new surface-mount Power Metal Strip resistor, in a package measuring 0.280 in. by 0.180 in. by 0.032 in. , also features low resistance values ranging from 1 milliohm to 100 milliohms.

Designed for use in current-sensing, voltage division, and pulse applications, the new WSH2818 resistor is intended for use in dc-to-dc conversion and voltage regulator modules (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 electromagnetic force (EMF), company officials said. 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 hazardous substance (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.

The WSH2818 is available in tape-and-reel packaging. Samples and production quantities of the new resistor are available now, with a lead time of eight to ten weeks for larger orders. Pricing for U.S. livery in 10,000 piece quantities starts at $0.59 per piece.