1210 shielded power inductor for automotive DC-DC input stages
The Murata DFE322520FD-4R7M=P2 is a 4.7 µH shielded wirewound inductor in a 1210 (3225 metric) surface-mount package, rated for 2 A continuous with a saturation current of 3.4 A. It is a straight drop into a DC-DC converter input filter for an engine-control unit or body-module supply rail — the 1210 footprint matches the standard inductor pad layout used across the DFE322520FD family.
Current ratings and the real derating story
The 2 A rated current is the DC current at which the inductance typically drops by 10% due to self-heating at 40°C ambient. The 3.4 A saturation current is the DC bias at which inductance falls by 30% — a hard ceiling for peak transient loads. In a typical 12 V-to-3.3 V buck converter switching at 1 MHz, the inductor ripple current is about 30% of the load; a 1.5 A continuous load leaves headroom before saturation, but a 2.5 A load step could push the core close to the 3.4 A limit. The 98 mΩ DCR is the winding resistance at 25°C. At 2 A the copper loss is 0.39 W; at 85°C ambient the DCR rises by about 20% (copper's temperature coefficient), pushing loss to ~0.47 W.