Inductance, current, and DC resistance — the filter choke's load-bearing numbers
This Murata LQH32NH181J23L is a drum-core wirewound inductor in the LQH32 series, rated 180 µH at 1 MHz test frequency with ±5% tolerance. The 60 mA continuous current rating and 9.12 Ω max DCR define the DC bias limit and the resistive loss — for a low-current filter or resonant tank, the DCR sets the I²R heating and the voltage drop across the part. The unshielded ferrite-core construction means the magnetic field extends beyond the package — adjacent traces or components on the same layer need clearance to avoid coupling, especially in a dense automotive ECU layout.
Rated AEC-Q200, this inductor meets the stress-test and reliability requirements for automotive-grade passive components — temperature cycling, mechanical shock, vibration, and solder-heat resistance are all qualified.
Self-resonant frequency and Q — where the inductor stops being an inductor
Self-resonant frequency is 6 MHz; above this point the parasitic capacitance dominates and the component behaves capacitively. The Q factor is 40 at 1 MHz, giving a usable inductive band from low frequency up to a few MHz — suitable for EMI filter chokes, LC tank circuits, or DC-DC converter output filters where the switching fundamental sits below 2 MHz.