2SB857-D Bipolar Transistor

• Type: PNP
• Collector-Emitter Voltage, max: -50 V
• Collector-Base Voltage, max: -70 V
• Emitter-Base Voltage, max: -5 V
• Collector Current − Continuous, max: -4 A
• Collector Dissipation: 40 W
• DC Current Gain (h_fe): 160 to 320
• Transition Frequency, min: 15 MHz
• Operating and Storage Junction Temperature Range: -45 to +150 °C
• Package: TO-220

Here is an image showing the pin diagram of this transistor.The 2SB857-D transistor can have a current gain of 160 to 320. The gain of the 2SB857 will be in the range from 60 to 320, for the 2SB857-B it will be in the range from 60 to 120, for the 2SB857-C it will be in the range from 100 to 200.Sometimes the "2S" prefix is not marked on the package - the 2SB857-D might only be marked "B857-D".The complementary NPN transistor to the 2SB857-D is the 2SD1133-D.The NZT660 (SOT-223) is the SMD version of the 2SB857-D transistor. These transistors are of the same type, have similar parameters and are designed for surface mounting.You can replace the 2SB857-D with the 2SA1262, 2SA1488, 2SA1488A, 2SA1634, 2SA1634-F, 2SA1635, 2SA1635-F, 2SA1742, 2SA1743, 2SA1744, 2SA770, 2SA771, 2SB633, 2SB633-F, 2SB858, 2SB858-D, BD204, BD244A, BD244B, BD244C, BD304, BD536, BD538, BD540A, BD540B, BD540C, BD544A, BD544B, BD544C, BD546A, BD546B, BD546C, BD798, BD800, BD802, BD808, BD810, BD950, BD952, BD954, BDT82, BDT82F, BDT84, BDT84F, BDT86, BDT86F, BDX78, D44C10, D44C11, D44C12, D44C7, D44C8, D44C9, D45C10, D45C11, D45C12, D45C7, D45C8, D45C9, D45H11, D45H11FP or D45H8.