The FC4B21300L from Panasonic Corporation is a MOSFET with Drain Source Resistance 55 to 225 milliohm, Drain Source Breakdown Voltage 12 V, Gate Source Voltage 8 V, Gate Source Threshold Voltage 0.35 to 1.4 V, Gate Charge 1.7 nC. Tags: Chip. More details for FC4B21300L can be seen below.