BST40 Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 350 V
• Collector-Base Voltage, max: 400 V
• Emitter-Base Voltage, max: 5 V
• Collector Current − Continuous, max: 0.1 A
• Collector Dissipation: 1.3 W
• DC Current Gain (h_fe): 0 to 40
• Transition Frequency, min: 70 MHz
• Operating and Storage Junction Temperature Range: -65 to +150 °C
• Package: SOT-89

Here is an image showing the pin diagram of this transistor.The BST40 transistor is marked as "AT2".The complementary PNP transistor to the BST40 is the BST16.