Parametric fit for DC-DC input and output filtering
The LQH43NN390K03L is a 39 µH drum-core wirewound inductor in Murata's LQH43 series, rated for 240 mA continuous current with a maximum DC resistance of 1.4 Ohm. This combination suits low-to-moderate current power rail filtering or energy storage in step-down converters where the inductor sees a DC bias below 240 mA. The unshielded construction means the magnetic field radiates beyond the component body — keep sensitive analog traces or high-impedance nodes at least a few millimeters away on the PCB layout to avoid coupling.
Thermal and frequency limits
The self-resonant frequency of 11 MHz defines the upper bound for inductive behavior; above this frequency the component behaves capacitively, so it is not suitable for switching converters running above roughly 2-3 MHz where the fundamental switching frequency and its harmonics approach SRF. The Q factor of 35 at 1 MHz indicates moderate AC loss — adequate for general-purpose filtering but not optimized for high-Q resonant tank circuits.
Sourcing and lifecycle position
No pin-compatible alternative is documented within the LQH43 family for this exact inductance and current rating.