The BL4022 from Galaxy Century Microelectronics is a MOSFET with Continous Drain Current 0.2 A, Drain Source Resistance 23000 to 25000 milli-ohm, Drain Source Breakdown Voltage 400 V, Gate Source Voltage ±20 V, Gate Source Threshold Voltage -1.5 to -3.3 V. Tags: Surface Mount. More details for BL4022 can be seen below.