Chip inductor improves NFC performance

January 30, 2017 // By Jean-Pierre Joosting
Murata has introduced the LQM18JN series of chip inductors for near field communication (NFC) applications, which overcome inherent problems associated with previous NFC designs to offer a better, more consistent performance.

NFC circuits utilize a chip inductor for impedance matching. However, due to the large currents that flow in an NFC matching circuit, the effect of magnetic saturation upon the inductor can seriously hinder the expected performance.

The LQM18JN series has been designed specifically for NFC matching circuits and is not easily impacted by magnetic saturation. In addition, its closed magnetic circuit configuration suppresses interference with surrounding components even at high mounting density, making it ideal for reducing the size of the NFC circuit. Small in size at 1.6- × 0.8-× 0.55-mm, and with a ±5 percent narrow deviation, they are ideal for impedance matching.

Aimed for use in NFC modules mounted in devices such as smartphones, the range currently embraces three inductors. The 100 nH rated LQM18JNR10J00 has a self-resonance frequency of 200 MHz and a current rating of 650 mA, the LQM18JNR12J00 is similarly rated at 120 nH, 150 MHz and 610 mA, and finally the LQM18JNR16J00 is rated at 160 Nh, 100 MHz and 550 mA. All three inductors share a Q rating of 8 or more.