2SB1157 Bipolar Transistor

• Type: PNP
• Collector-Emitter Voltage, max: -100 V
• Collector-Base Voltage, max: -100 V
• Emitter-Base Voltage, max: -5 V
• Collector Current − Continuous, max: -5 A
• Collector Dissipation: 60 W
• DC Current Gain (h_fe): 60 to 200
• Transition Frequency, min: 20 MHz
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: TO-3PF

Here is an image showing the pin diagram of this transistor.The 2SB1157 transistor can have a current gain of 60 to 200. The gain of the 2SB1157-P will be in the range from 100 to 200, for the 2SB1157-Q it will be in the range from 60 to 120, for the 2SB1157-S it will be in the range from 80 to 160.Sometimes the "2S" prefix is not marked on the package - the 2SB1157 might only be marked "B1157".The complementary NPN transistor to the 2SB1157 is the 2SD1712.The BDP954 (SOT-223) is the SMD version of the 2SB1157 transistor. These transistors are of the same type, have similar parameters and are designed for surface mounting.You can replace the 2SB1157 with the 2SA1141, 2SB1054, 2SB1055, 2SB1056, 2SB1057, 2SB1158, 2SB1159, 2SB1160 or 2SB1161.