Signal-line ferrite bead, 0402, AEC-Q200
The Murata BLM15AG102SZ1D is a single-line ferrite bead from the EMIFIL®, BLM15 series, housed in a standard 0402 (1005 metric) footprint. It provides 1 kOhms impedance at 100 MHz, sized for suppressing conducted noise on signal lines in space-constrained designs. Rated for 300 mA continuous current with a maximum DC resistance of 650 mOhm — the DCR sets the voltage drop and self-heating under load, so the 300 mA ceiling is the practical limit before the temperature rise exceeds the bead's derating curve.
Impedance vs current — the real-world derating
The 1 kOhms impedance is specified at 100 MHz — the bead's peak suppression band. At lower frequencies the impedance drops; at DC it is just the DCR of 650 mOhm, so the bead does not attenuate power-line ripple below the MHz range. Under bias current, the ferrite core saturates and the effective impedance decreases. At 300 mA the bead may deliver only 50–60% of its rated impedance at 100 MHz — design the noise margin with this derating in mind, especially on supply lines where the DC bias is continuous.
Procurement and lifecycle status
The base product number BLM15AG covers the family; the full suffix (102SZ1D) encodes the impedance value, material grade, and packaging. Tape-and-reel (TR) or cut-tape (CT) options are listed — the reel quantity is standard for 0402 chip beads.