News and New Products

Bourns hot-dips trimmers to eliminate tin whiskers

By Margery Conner, Technical Editor -- EDN, 2/12/2009

Tin whiskers—electrically conductive, crystalline structures that grow from surfaces on which tin is the final finish—have been the bane of electronic products since 2007. During that year, a European ROHS (restriction-of-hazardous-substances) directive essentially banned the use of lead in many electronic devices. However, the lead-free tin solder replacement is prone to whiskers, which can cause short circuits, interference, and unreliability. To virtually eliminate tin whiskers in its trimmers, Bourns’ line of ROHS-compliant cermet-wire-terminal trimming potentiometers now uses a new, hot-dipped-tin process. Although the process costs more than the matte-finished leads the company previously used, Bourns is not passing the additional cost on to customers, seeing it as an opportunity to gain market share.