240 Ohm at 100 MHz — the suppression target
The BLM15BC241SN1D is a single-line ferrite bead from Murata's EMIFIL® BLM15 series, delivering 240 Ohms impedance at 100 MHz. That impedance peak sits right where most conducted EMI from switching regulators and digital clocks radiates — the bead absorbs that energy as heat rather than reflecting it back onto the trace. Rated for 250 mA continuous current with a maximum DC resistance of 700 mOhm.
0402 footprint and temperature range
Housed in a standard 0402 (1005 metric) package — 1.00 mm x 0.55 mm, seated height 0.55 mm max. The small footprint fits dense layouts near the noise source (right at the IC pin or connector), which is exactly where a ferrite bead does its best work: before the trace radiates. The ferrite material's impedance curve shifts with temperature, but within this band the 240 Ohm peak stays within spec.