18 µH, 340 mA — the DC bias limit and loss budget
The LQH43NN180J03L is a Murata drum-core wirewound inductor delivering 18 µH ±5% with a rated current of 340 mA. The 820 mOhm DCR sets the resistive loss at 96 mW at rated current — a figure that drives self-heating and must be factored into the power budget, especially in compact 1812 layouts where airflow is limited.
Unshielded ferrite core — layout coupling awareness
The ferrite core is unshielded, so the magnetic field extends beyond the component body. In a dense PCB, adjacent traces carrying sensitive analog signals or high-speed edges can pick up coupled noise — keep a keep-out zone of at least one component width around the inductor, or orient it so the field axis points away from noise-sensitive circuitry. The self-resonant frequency is 17 MHz, and the Q factor measures 35 at 1 MHz. Above the SRF, the inductor behaves capacitively — the usable inductance holds within 10% up to about 5 MHz for most designs, beyond which the impedance roll-off must be verified against the circuit's operating frequency.
1812 footprint — board integration note
The surface-mount footprint is standard across the LQH43 series — a single land pattern serves the full inductance range, simplifying last-minute value changes without a board spin.