2SA643O Bipolar Transistor

• Type: PNP
• Collector-Emitter Voltage, max: -20 V
• Collector-Base Voltage, max: -40 V
• Emitter-Base Voltage, max: -5 V
• Collector Current − Continuous, max: -0.5 A
• Collector Dissipation: 0.5 W
• DC Current Gain (h_fe): 70 to 140
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: TO-92

The 2SA643O 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, base, and collector leads.
Here is an image showing the pin diagram of this transistor.The 2SA643O transistor can have a current gain of 70 to 140. The gain of the 2SA643 will be in the range from 40 to 400, for the 2SA643G it will be in the range from 200 to 400, for the 2SA643R it will be in the range from 40 to 80, for the 2SA643Y it will be in the range from 120 to 240.Sometimes the "2S" prefix is not marked on the package - the 2SA643O might only be marked "A643O".The complementary NPN transistor to the 2SA643O is the 2SD261O.The KSA643O is the TO-92 version of the 2SA643O.You can replace the 2SA643O with the 2N4402, 2SA695, 2SB564A, 2SB564AO, KSA643, KSA643O, KSB564A, KSB564AO, KTC9012, MPS3702, MPS6535, MPS6562, MPS6563, MPS6651, MPS6651G, MPS6652, MPS6652G, MPSW51, MPSW51A, MPSW51AG, MPSW51G, S9012 or SS9012.