Laminated low temperature co-fired ceramic ferrite materials and the applications for high current POL converters

Low temperature co-fired ceramic (LTCC) ferrite materials are a group of materials for magnetic substrate of integrated power converters. The inductors can be fabricated in the substrate so that the power density of the converter can be dramatically increased. There are three types of commercial LTCC ferrite materials from ESL ElectroScience®: 40010, 40011 and 40012. However, these materials are not optimized for high current integrated point-of-load (POL) converters. In this paper, the LTCC materials are improved by laminating different LTCC green tapes. The lamination impact to the microstructure and composition is analyzed and discussed. After comparisons, a new LTCC material with better composition for power converters is found. Both magnetic characterization and planar inductor demonstration have shown that the new material is more suitable for high current integrated POL converter applications.