The BL3439 from GALAXY CENTURY MICROELECTRONICS is a MOSFET with Continous Drain Current -0.4 to 0.75 A, Drain Source Resistance 370 to 900 milli-ohm, Drain Source Breakdown Voltage -30 to 30 V, Gate Source Voltage ±12 V, Gate Source Threshold Voltage -1.95 to 1.5 V. Tags: Surface Mount. More details for BL3439 can be seen below.