Commercialization of Microchip Transformers
(Balun Transformers) for Digital TV Tuners
-DXW21BN, DXP18BN Series-
[Text]
Murata Manufacturing Co., Ltd. has commercialized microchip transformers (balun transformers),
which are used to convert between unbalanced-balanced signals in the antenna inputs of TV tuner
circuits for terrestrial digital broadcast compatible compact mobile devices.
Up to now balun transformers for TV tuners have been made by winding wire around a
spectacle-shaped ferrite core, and are widely used in large-scale devices such as TVs and desktop
PCs. However, these kinds of transformers are about 5 x 5 mm in size, and therefore unsuited for
usage in compact mobile devices such as mobile phones, notebook PCs, and portable gaming
devices. Muratas newly developed balun transformers represent the industrys smallest microchip
transformers, featuring an ultra small, ultra low-profile design achieved through optimized
internal circuits, utilizing wire wound and film forming technologies developed by Murata. The
wire wound type model is 2.0 x 1.2 mm (EIA Code: 0805), and the film type is 1.6 x 0.8 mm (EIA
Code: 0603). Note that since the film type does not connect externally to the transformer and has a
conversion rate of 1:4, it is suited to a variety of circuits.
Compared to conventional balun transformers made with wire wound around a spectacle-shaped
ferrite core, the wire wound type reduces the required mounting space by approximately 75%, and
height by approximately 40%, while the film type can cut mounting space by 95%, and height by
80%. Thus, these microchip transformers can contribute significantly to enabling smaller, slimmer
mobile device for terrestrial digital broadcasts, which are expected to become increasingly
popular.