4.7 µH wirewound inductor for automotive and industrial DC-DC filtering
The Murata LQH32NH4R7J23L is a 4.7 µH drum core wirewound inductor in the LQH32 series, rated for 420 mA continuous current with a maximum DC resistance of 252 mOhm. The 1210 (3225 Metric) footprint and surface-mount package allow pick-and-place assembly on standard PCB layouts without special handling.
What the key ratings mean for your power-stage design
The 420 mA current rating is the DC bias current at which the inductance typically drops by 10% from the nominal 4.7 µH value — the actual saturation current is higher, but the rated current is the design limit for maintaining inductance within the application's tolerance budget. 252 mOhm maximum DCR at 25 °C produces an I²R loss of roughly 44 mW at full rated current — this self-heating raises the internal temperature above ambient, so the 125 °C operating limit must be derated for the temperature rise from the winding loss. A self-resonant frequency of 55 MHz means the inductor behaves inductively up to that point; above 55 MHz the parasitic capacitance dominates and the component becomes capacitive — this sets the upper frequency limit for the DC-DC converter's switching frequency or the filter's cutoff. The Q factor of 20 at 1 MHz indicates the ratio of inductive reactance to effective resistance at that test frequency — a higher Q means lower energy loss per cycle, which matters for resonant circuits or RF filtering at 1 MHz.