30 Ohm at 100 MHz — where this bead sits in the BLM15 family
The BLM15AX300SN1D is a single-line ferrite bead from Murata's EMIFIL® BLM15 series, in the 0402 (1005 metric) footprint. Its 30 Ohm impedance at 100 MHz targets moderate-frequency noise on a power rail or signal line — not the high-impedance suppression of a 1 kOhm bead, but enough to knock down switching harmonics without dropping much DC voltage.
1.1 A current rating and 60 mOhm DCR — the DC trade-off
Rated for 1.1 A continuous with a maximum DC resistance of 60 mOhm. At full current the resistive loss is about 73 mW — negligible for most rails, but worth checking if the bead sits on a 1.8 V or 1.2 V supply where that drop eats into the voltage margin.