PBHV8540T Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 400 V
• Collector-Base Voltage, max: 500 V
• Emitter-Base Voltage, max: 6 V
• Collector Current − Continuous, max: 0.5 A
• Collector Dissipation: 0.3 W
• DC Current Gain (h_fe): 100
• Transition Frequency, min: 30 MHz
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: SOT-23

Here is an image showing the pin diagram of this transistor.The PBHV8540T transistor is marked as "W4".The complementary PNP transistor to the PBHV8540T is the PBHV9040T.You can replace the PBHV8540T with the STR1550.