AEC-Q200 wirewound in the 1812 footprint
The Murata LQH43NH390J03L is a 39 µH drum-core wirewound inductor in the standard 1812 (4532 Metric) surface-mount package, qualified to AEC-Q200 for automotive-grade reliability. Rated for 230 mA DC with a maximum DC resistance of 960 mOhm, the part suits low-to-moderate current filtering in power supply inputs, DC-DC converter output stages, and noise suppression on signal lines where the 39 µH value sets the corner frequency.
What the ratings mean for your BOM
The 39 µH inductance with ±5% tolerance gives a tight window for filter designs — the corner frequency stays within 5% of the target without trimming, which matters for EMI filter cut-offs and LC tank circuits. A quality factor of 35 at 1 MHz tells you the ratio of stored energy to energy lost per cycle at that frequency; lower Q means more core loss, so this part is better suited for power filtering below 1 MHz than for high-Q resonant tank applications. The self-resonant frequency of 11 MHz sets the upper bound for inductive behaviour — above 11 MHz the part looks capacitive, so keep the operating frequency well below that for effective filtering.
Board-fit and rework reality
Unshielded construction means the magnetic field extends beyond the package — keep sensitive traces or other magnetics at least one body width away to avoid coupling. The ±5% tolerance is marked on the body with a three-digit code; orientation is unambiguous from the marking, so hand-rework after a reflow miss is straightforward with hot air — the part lifts cleanly without pad damage if the board is preheated to 100°C.
Sourcing and compliance
AEC-Q200 qualification means the part has passed the full suite of automotive stress tests (thermal shock, moisture resistance, mechanical shock, vibration) and is suitable for under-hood, chassis, and cabin electronics without additional screening.