1.5 µH wirewound inductor — BOM-fit and last-buy reality
The Murata LQH31MN1R5K03L is a 1.5 µH drum-core wirewound inductor in the LQH31 series, packaged in a standard 1206 (3216 Metric) footprint for surface-mount assembly. Rated for 155 mA continuous current with a maximum DC resistance of 1.3 Ohm — the DCR sets the I²R heating and DC voltage drop in the supply rail, so the 155 mA figure is the thermal limit at 85°C ambient, not a hard saturation current. The unshielded ferrite-core construction means the magnetic field radiates into the surrounding board area — adjacent traces carrying sensitive analog or RF signals need keep-out spacing to avoid coupled noise.
Q factor and self-resonant frequency — where it works
A minimum Q of 35 at 10 MHz and a self-resonant frequency of 75 MHz define the useful band: below resonance the inductor behaves as an inductor; near and above it, parasitic capacitance dominates and the impedance rolls off. For a 1.5 µH part, 75 MHz SRF means the inductor is usable in low-MHz switching converters (buck/boost at 1–3 MHz) and as a decoupling element in RF bias circuits up to about 30 MHz before the Q drop becomes significant.
Last Buy — procurement window closing
Murata has set the LQH31MN1R5K03L to Last Buy status — the manufacturer is winding down production, so remaining inventory is the final available stock through independent distribution. For a BOM line that depends on this exact inductance, tolerance, and footprint, the decision is to secure the lifetime buy quantity now or qualify a replacement before the supply dries up.