600 Ohms at 100 MHz — the suppression point
The BLM15BD601SN1D is a single-line ferrite bead from Murata's EMIFIL BLM15 series, delivering 600 Ohms impedance at 100 MHz. That impedance peak sits right where conducted EMI from switching regulators and digital clocks radiates — the bead turns that energy into heat instead of letting it ride the trace out to the cable or antenna.
Current ceiling and DC penalty
Rated for 200 mA continuous current — push past that and the ferrite material saturates, dropping the effective impedance. The 650 mOhm max DCR means a 130 mV drop at full rated current, which matters if the rail is tight on margin.
Temperature range and rework reality
The 0402 package (1.00 mm x 0.55 mm) is small enough that the hot-air rework profile is forgiving: the part reaches reflow temperature before the adjacent components do, so you can lift it without disturbing the neighbour. Pin 1 is marked by the orientation dot on the top face — check it under magnification before placing, because at this size the dot is easy to miss.