PN3644 Bipolar Transistor

• Type: PNP
• Collector-Emitter Voltage, max: -45 V
• Collector-Base Voltage, max: -45 V
• Emitter-Base Voltage, max: -5 V
• Collector Current − Continuous, max: -0.5 A
• Collector Dissipation: 0.625 W
• DC Current Gain (h_fe): 80 to 240
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: TO-92
• Electrically Similar to the Popular 2N3644 transistor

The PN3644 is manufactured in a plastic TO-92 case. When looking at the flat side with the leads pointed downward, the three leads emerging from the transistor are, from left to right, the emitter, collector, and base leads.
Here is an image showing the pin diagram of this transistor.The 2SA1313 (SOT-23), 2SA1518 (SOT-23), 2SA1519 (SOT-23), 2SA1520 (SOT-23) and 2SA1521 (SOT-23) is the SMD version of the PN3644 transistor. These transistors are of the same type, have similar parameters and are designed for surface mounting.You can replace the PN3644 with the 2SA1020, 2SA1283, 2SA1315, 2SA1522, 2SA1523, 2SA1524, 2SA1525, 2SA1526, 2SA1527, 2SA1528, 2SA1529, 2SA1619A, 2SA200, 2SA984, 2SA984K, 2SA993, 2SB560, 2SB647, 2SB764, BC636, KSA708C, KSA931, KTA1281, KTA200, KTB764 or PN3645.