2SD1691 Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 60 V
• Collector-Base Voltage, max: 60 V
• Emitter-Base Voltage, max: 7 V
• Collector Current − Continuous, max: 5 A
• Collector Dissipation: 20 W
• DC Current Gain (h_fe): 100 to 400
• 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 2SD1691 transistor can have a current gain of 100 to 400. The gain of the 2SD1691-K will be in the range from 200 to 400, for the 2SD1691-L it will be in the range from 160 to 320, for the 2SD1691-M it will be in the range from 100 to 200.Sometimes the "2S" prefix is not marked on the package - the 2SD1691 might only be marked "D1691".The complementary PNP transistor to the 2SD1691 is the 2SB1151.The BDP949 (SOT-223) is the SMD version of the 2SD1691 transistor. These transistors are of the same type, have similar parameters and are designed for surface mounting.You can replace the 2SD1691 with the KSD1691.