Evaluation of LTCC capacitors and inductors in DC/DC converters

Low temperature co-fired ceramic (LTCC) technology has been proved to be an effective way to realize system integration. By using this technology, passive components in a DC/DC converter could be integrated into a passive substrate. This paper presents fabrication and evaluation of LTCC capacitors and inductors and summarizes challenges of applying LTCC technology to DC/DC converters. Four capacitors are made; two of them are made with single layer high permittivity thick film paste, and maximum 1.1 ¿F capacitance is obtained; the other two are made with multilayer low permittivity LTCC tapes, maximum 30 nF capacitance is obtained. A 70 nH LTCC inductor is also fabricated with ferrite tapes. It is tested in a 1.2 MHz buck converter and a 30 MHz class ¿
₂
DC/DC converter. Finally, challenges of conductor resistance, capacitor tape permittivity, and shrinkage matching are discussed and summarized.