Load characteristics of a spiral coil type thin film microtransformer

A spiral coil type thin film microtransformer with a size of 2.4*3.1 mm/sup 2/ is fabricated using photolithography techniques for application in megahertz region switching regulators. An amorphous magnetic film of a multilayered CoNbZr/SiO/sub 2/ is used as a magnetic core. Load characteristics are measured at 10 MHz. A comparatively high efficiency of 67% and an acceptable excitation current of 25 mA are obtained, in spite of the small size of the microtransformer.<
>