To combat this, the sulphur resisting ASC series offers standard sizes from 0402 to 2512, and values 1R0 to 10M?, all featuring special terminations that withstand sulphur-bearing gasses. The conductors, resistive element, glass inner protection and epoxy outer protection are applied to a 96% alumina substrate, and the chips are supplied with wrap-around terminations suitable for soldering. Terminations have an electro-plated nickel barrier and a RoHS-compliant 100 percent matt tin finish.
Sulphide growth resistance is demonstrated by testing in accordance with ASTM international standard B809-95(2008): Standard Test Method for Porosity in Metallic Coatings by Humid Sulfur Vapor (Flowers-of-Sulfur). Components in the new ASC thick-film chip resistor series are available now, and supplied on tape-and-reel for automated assembly.