18 µH wirewound inductor in 1206 — last-buy timing
The LQH31MN180K03L is a Murata drum-core wirewound inductor delivering 18 µH at 1 MHz test frequency, rated for 85 mA continuous current. With a maximum DC resistance of 4.42 Ohm, the I²R loss at full rated current is about 32 mW — negligible for most signal filtering or low-power DC-DC output ripple applications, but the DCR does set a floor on efficiency in a boost or buck inductor position. The unshielded construction means the external magnetic field couples into adjacent traces or components — layout separation from sensitive analog or RF nodes is advisable. The self-resonant frequency is 15 MHz, so the usable inductance band stops well before that; above SRF the part behaves capacitively.
Last-buy lifecycle and supply posture
Murata has designated the LQH31MN180K03L as Last Buy — the manufacturer's end-of-life notice is active, and the remaining production window is finite. Sourced through independent distribution channels against an RFQ. The 1206 footprint and 18 µH / 85 mA rating are the parameters to match for a drop-in replacement.