2SD634 Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 80 V
• Collector-Base Voltage, max: 80 V
• Emitter-Base Voltage, max: 5 V
• Collector Current − Continuous, max: 7 A
• Collector Dissipation: 40 W
• DC Current Gain (h_fe): 2000 to 15000
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: TO-220

Here is an image showing the pin diagram of this transistor.Sometimes the "2S" prefix is not marked on the package - the 2SD634 might only be marked "D634".The complementary PNP transistor to the 2SD634 is the 2SB674.You can replace the 2SD634 with the 2N6044, 2N6044G, 2N6045, 2N6045G, 2N6388, 2N6388G, 2SD1196, 2SD1415, 2SD1415A, 2SD1830, 2SD633, BD537, BD543B, BD543C, BD545B, BD545C, BD647, BD649, BD651, BD799, BD801, BD809, BD899, BD899A, BD901, BDT63A, BDT63B, BDT63C, BDT65A, BDT65B, BDT65C, BDT83, BDT83F, BDT85, BDT85F, BDT87, BDT87F, BDW41, BDW41G, BDW42, BDW42G, BDW43, BDW73B, BDW73C, BDW73D, BDX33B, BDX33BG, BDX33C, BDX33CG, BDX33D, BDX53B, BDX53BG, BDX53C, BDX53CG, BDX53D, BDX53E, BDX53F, BDX77, D44H11, D44H11FP, MJE15028, MJE15028G, MJE15030, MJE15030G, MJF15030, MJF15030G, TIP101, TIP101G, TIP102, TIP102G, TIP131, TIP131G, TIP132, TIP132G, TIP141T, TIP142T or TTD1415B.