2SD1684 Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 100 V
• Collector-Base Voltage, max: 120 V
• Emitter-Base Voltage, max: 6 V
• Collector Current − Continuous, max: 1.5 A
• Collector Dissipation: 10 W
• DC Current Gain (h_fe): 100 to 400
• Transition Frequency, min: 120 MHz
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: TO-126

Here is an image showing the pin diagram of this transistor.The 2SD1684 transistor can have a current gain of 100 to 400. The gain of the 2SD1684-Q will be in the range from 100 to 200, for the 2SD1684-S it will be in the range from 140 to 280, for the 2SD1684-T it will be in the range from 200 to 400.Sometimes the "2S" prefix is not marked on the package - the 2SD1684 might only be marked "D1684".The complementary PNP transistor to the 2SD1684 is the 2SB1144.The FMMT624 (SOT-23) is the SMD version of the 2SD1684 transistor. These transistors are of the same type, have similar parameters and are designed for surface mounting.You can replace the 2SD1684 with the 2SC3117, 2SC3902, 2SD1724, 2SD1725 or MJE244.