2SA642O Bipolar Transistor

• Type: PNP
• Collector-Emitter Voltage, max: -25 V
• Collector-Base Voltage, max: -30 V
• Emitter-Base Voltage, max: -5 V
• Collector Current − Continuous, max: -0.3 A
• Collector Dissipation: 0.4 W
• DC Current Gain (h_fe): 70 to 140
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: TO-92

The 2SA642O 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 2SA642O transistor can have a current gain of 70 to 140. The gain of the 2SA642 will be in the range from 70 to 400, for the 2SA642G it will be in the range from 200 to 400, for the 2SA642Y it will be in the range from 120 to 240.Sometimes the "2S" prefix is not marked on the package - the 2SA642O might only be marked "A642O".The complementary NPN transistor to the 2SA642O is the 2SD227O.The MMBT4125 (SOT-23) is the SMD version of the 2SA642O transistor. These transistors are of the same type, have similar parameters and are designed for surface mounting.The KSA642O is the TO-92 version of the 2SA642O.You can replace the 2SA642O with the 2N4402, 2SA696, 2SB564A, 2SB564AO, KSA642, KSA642O, KSB564A, KSB564AO, KTC9012, MPS3702, MPS6535, MPS6562, MPS6651, MPS6651G, MPS6652, MPS6652G, MPSW51, MPSW51A, MPSW51AG, MPSW51G or S9012.