SMD and Leaded Ceramic Capacitors for High Temperature Applications

Abstract

For high temperature applications at 150°C or above, such as in electronics for down-hole drilling, geothermal energy generation, power electronics and automotive under the hood electronics, a robust dielectric material is necessary for capacitors. Common X7R and X8R type ceramic capacitors are designed for applications up to 125°C and 150°C, respectively. At temperatures above 150°C, these types of capacitors typically suffer from degradation of reliability performance and severe reduction in capacitance, especially under DC bias conditions. Recently, a Class-I dielectric material has been developed using Nickel electrodes for high temperature application up to 200–250°C. Due to its linear dielectric nature, this material exhibits highly stable capacitance as a function of temperature and voltage. Multi-layer ceramic capacitors (MLCCs) made from this material can be qualified as X9G. This paper will report electrical properties and reliability test data on these Class-I type ceramic capacitors in SMD chip and leaded configurations at 150–200°C and above along with a discussion of possible mechanisms behind the robust reliability of this high temperature dielectric.