220 µH in a 1210 footprint — what the ratings mean for your filter or bias choke
The LQH32DN221K23L is a 220 µH unshielded wirewound inductor from Murata's LQH32 series, in a standard 1210 (3225 Metric) surface-mount package. At 70 mA rated current, it handles DC bias for low-power supply rails or signal-path filtering without saturating the ferrite core. The 10.92 Ohm maximum DCR means I²R loss is about 53 mW at full rated current — fine for most low-current circuits, but worth checking if the inductor sits in a high-ambient-temperature zone where copper resistance climbs further. Self-resonant frequency is 6.8 MHz; above that the impedance turns capacitive, so this part suits switching frequencies well below that — think 100 kHz to 1 MHz buck converters or EMI filtering in that band.
Unshielded construction — placement and coupling trade-off
Unshielded means the magnetic field radiates beyond the component body. Keep a gap to adjacent traces or sensitive analog circuits — a rule of thumb is at least one part width (3.2 mm) of clearance to avoid parasitic coupling. The ferrite core material handles the 220 µH value in a compact footprint, but the unshielded nature limits how tightly you can pack it alongside other magnetics or high-impedance nodes.