47 µH wirewound in a 1206 footprint — what the ratings mean for the BOM
The LQH31MN470K03L: The 47 µH inductance at 1 MHz test frequency places this part in the mid-value range for the LQH31 series, suited for LC filtering, DC-DC input/output ripple attenuation, and resonant tank circuits where the self-resonant frequency of 10 MHz sets the usable band — above that the inductor behaves capacitively. Rated for 55 mA continuous current; the 10.4 Ohm max DCR means at full rated current the DC loss is about 31 mW, which is manageable in a 1206 package but will raise the internal temperature above ambient — derate if the board sees elevated ambient or if the current is near the limit continuously. Q factor of 40 at 2.5 MHz indicates moderate AC loss at that frequency — adequate for general-purpose filtering but not optimal for high-Q tuned circuits where a Q above 80 would be preferred. The unshielded construction means magnetic flux couples into nearby traces; keep sensitive analog or RF traces a few mm away on the layout.
Last Buy — sourcing window is closing
Murata lists the LQH31MN470K03L as Last Buy — the manufacturer has announced end-of-life and is taking final orders. Once the LTB window closes, the only channel will be surplus inventory. For a BOM that already uses this part, now is the time to secure lifetime buy quantities or qualify a drop-in alternative. The 1206 footprint and 47 µH value are common enough that a shielded or higher-current replacement from another series may fit the same pad layout — but pin-compatibility is not guaranteed without testing.