1.8 µH wirewound for filtering and resonant circuits
The LQH31MN1R8J03L is a 1.8 µH drum core wirewound inductor from Murata's LQH31 series, built on a ferrite core and terminated in a standard 1206 (3216 metric) surface-mount footprint. Rated for 150 mA continuous current with a DC resistance of 1.6 Ohm, the I²R loss at full rated current is 36 mW — a factor when the inductor sits in a power supply rail or a low-impedance bias tee. The self-resonant frequency of 60 MHz defines the upper bound of the usable band; above SRF the component behaves capacitively, so it suits switching frequencies up to the low tens of MHz and RF bias/choke applications below 60 MHz.
Layout consideration: unshielded construction
Unshielded means the magnetic field radiates into the surrounding PCB area — adjacent traces carrying high-speed or sensitive analog signals need a keep-out zone or a grounded copper pour between them and this inductor.
Q factor and test conditions
Q factor is specified as 35 minimum at 10 MHz — moderate selectivity typical of a general-purpose ferrite-core wirewound; for narrowband resonant tank circuits a higher-Q ceramic-core part would be a better fit. Inductance is tested at 1 MHz, and the ±5% tolerance holds across the operating temperature range.