A new Mn-Zn ferrite for high-speed data transmission applications in telecommunication networks

In DSL and ISDN telecommunication technologies, advanced modems are used to increase data transmission speed over regular UTP lines. The good operation of these modems requires a low signal distortion of the polycrystalline Mn-Zn ferrites used as transformer core components at low fields. Given that distortion is directly related to the non-linearity of the B-H loop, the purpose of this study was to determine the basic guidelines for the development of Mn - Zn ferrites with a linear B-H behaviour. It appears that retarding the Fe2+-Fe3+ electron exchange with appropriate dopants such as TiO2 leads to the manufacturing of Mn-Zn ferrite materials that exhibit high initial permeability (similar to 8500), low losses (tan delta/mu < 1.37 x 10(-6) at 25 degrees C, 10 kHz, 0.25 mT and tan delta/mu < 16 x 10(-6) at 25 degrees C, 100 kHz, 0.25 mT) and low hysteresis material constant ( < 0.17 x 10(-3)), that are suitable for DSL and ISDN transformer applications. (C) 2006 Elsevier B.V. All rights reserved.