RELAXOR DIELECTRIC MATERIALS FOR MULTILAYER CERAMIC CAPACITOR IN HIGH-TEMPERATURE APPLICATIONS

A relaxer ceramic dielectric based on the (Pb, Ba)[(Zn1/3Nb2/3)(Mg1/3N b2/3)Ti]O-3 system has been developed for multilayer ceramic capacitor s (MLC) in high-temperature applications. This dielectric material is designed to exhibit a capacitance peak value at around 60 degrees C, w hich is a typical temperature inside a switching mode power supply (SM PS). An MLC fabricated using this new dielectric and fired at 1050 deg rees C has a relative dielectric constant of 9000 and a CR product (ca pacitance x resistance) of 8000 Ohm F at room temperature. However, at 60 degrees C the relative dielectric constant is 14000 and the CR pro duct is 4000 Ohm F. The change in capacitance with temperature is less than -30% from 0 to 125 degrees C. This makes the new MLC a promising candidate for use as a filter capacitor in high-frequency SMPS.