High Temperature X8r Ceramic Capacitor

Multi-layer ceramics capacitor (MLCC) has many advantages, such asminiaturization, high value of capacitance, realization in chips and mass production.And the trend of multi-function has become obvious with the continuous developmentof technology. The technology of multi-function is mainly developed towardsmultilayer ceramic capacitors used in RF band, in microwave band, in pulse circuits, inhigh voltage transmission lines, in power switching circuits and in circuits of hightemperature in harsh environment.This paper studied the high-temperature X8R multilayer ceramic capacitors usedin varies electronic systems operating in high temperature and harsh environment(newtypes of electronic control devices on vehicles, logging tools in exploration system foroilfields, electronic systems for aircraft engines etc.) The research includes thematerial,the design of structure and the realization of mass production, that meets thedomestic demand.The device discussed in this paper is commensurate with that produced byU.S.NOVACAP. It applies not only for the electric systems on vehicles and explorationfor oilfields, but also for the engines in fighter aircraft. The technical standardGJB912A-98in the design is equivalent to U.S. military standards of MIL-55681.The test results of the device designed in this paper are as follows. The range ofoperating temperature is-55oC~+150oC. The maximum of loss tangent at25oC is0.025(2.5%). The parameters tested at1kHz is1.0±0.2VRMS,25oCS. Thetemperature at150o C is±15%for ΔC/C at maximum. The value of insulationresistance is larger than100G or1000F at25oC and is larger than10G or100Fwhen the temperature is150oC. The rated working voltage is less than200V. The testvoltage is250%. The aging rate is less than2.0%./decade.