Chomerics introduces two new spray-on EMI shield materials

Chomerics Europe has introduced two innovative new coatings that provide shielding for semiconductor packages and other board- and package-level electronic components that require protection from EMI. CHO-SHIELD 604 and CHO-SHIELD 571 are highly-conductive materials suited for high-volume applications. They are applied using precise spray equipment to coat the target surface. The new silver-filled conductive coating materials can provide a cost-effective, space- and weight-saving alternative to metal cans in a wide variety of applications.   CHO-SHIELD 604 is a one component silver-filled polyurethane material that achieves shielding effectiveness in the region of 100 dB (10 MHz to10 GHz) and 80 dB at frequencies between 10 and 18 GHz. CHO-SHIELD 571 is a two-component silver-filled epoxy with shielding performance in excess of 120 dB (10 MHz to10 GHz) and 100 dB between 10 and 18 GHz. Maximum surface resistivity for both materials is 10 m?/? at one mil.   Both materials are flexible and offer a high degree of environmental stability. CHO-SHIELD 571 has a CTE (coefficient of thermal expansion) designed to match that of epoxy moulding compounds common in electronic-component packaging. This helps the coating achieve an especially strong bond with component surfaces.  Both materials withstand wave-solder temperatures in excess 500 °F (262 °C) and they offer a continuous upper operating temperature of +85 °C. Chomerics