Multilayer power inductors suit mobile NFC applications

26th May 2015

Barney Scott

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TDK Corporation has expanded its portfolio of multilayer power inductors with the MLJ1608 high-performance series. Complementing the existing MLF1608 series of multilayer power inductors for signal lines, the MLJ1608 series was designed for use in near field communications and power line applications, especially in smartphones, tablets and NFC modules.

The multilayer power inductors feature a high Q of up to 30 at 13.56MHz, a narrow inductance tolerance of just ±5%, and excellent magnetic shielding characteristics. They thus meet all the requirements for coils used in NFC applications and are especially well-suited for the LC filtering circuit between the NFC control chip and antenna.

The current lineup covers inductance values from 160 to 560nH. Thanks to their high rated currents ranging from 550 to 750mA, they ensure operational stability even when handling the AC signal currents in the range of 100 to 300mA that are encountered when the communication circuit is active. The compact IEC 1608 package (EIA 0603) of the MLJ1608 series has a footprint of 1.6x0.8x0.8mm. Mass production of the MLJ1608 series began in April 2015.

The MLJ1608 series relies on a recently-developed low-loss ferrite material from TDK which makes it possible to realise lower loss values with AC signals than achieved with similar sized wound coils. The superposition performance of the ferrite material has also been improved, resulting in characteristics that are on a par with those of conventional wound coils at the 300mA peak current levels flowing in the NFC circuit.

An additional MLJ1005 series in an IEC 1005 (EIA 0402) package is currently under development and will add products suitable for low power NFC modules and applications requiring very small dimensions.