Class-D amplifiers, which are used in devices such as smartphones and audio equipment, have the advantages of being compact and highly efficient, but crucially require countermeasures against noise generated by their high-speed switching. TDK has an extensive lineup of products which can provide effective noise countermeasures while ensuring high sound quality and without affecting signals. This article describes the applications and effectiveness of these products in speaker lines for various devices which use Class-D amplifiers.

TDK has developed TCM0403R common mode filters, which have realized a significant size reduction compared to the existing thin-film common mode filters. This size reduction was made possible through the application of unique thin-film processing techniques, developed for HDD heads. These filters are ideal as a noise suppression measure in mobile devices such as smartphones and tablets, for which conservation of space is demanded.