Core parametrics for the DC-DC stage
The Murata DFE252010F-4R7M=P2 is a 4.7 µH shielded power inductor in the DFE252010F series, designed for surface-mount power conversion circuits. Rated at 1.4 A DC with a saturation current of 2.2 A, this part handles the ripple current in a buck converter without entering hard saturation — the iron powder core's soft saturation characteristic means inductance rolls off gradually above Isat rather than collapsing abruptly. Maximum DC resistance is 240 mOhm; at 1.4 A the I²R loss is 0.47 W, which must be accounted for in the thermal design of the board.
The shielded construction reduces magnetic flux leakage, allowing placement near sensitive analog or RF circuitry without coupling issues. Operating temperature range is -40°C to +125°C, covering automotive under-hood and industrial ambient environments; the iron powder core maintains stable inductance across this band under bias.