2SD1221-GR 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: 3 A
• Collector Dissipation: 20 W
• DC Current Gain (h_fe): 150 to 300
• Transition Frequency, min: 3 MHz
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: TO-252

Here is an image showing the pin diagram of this transistor.The 2SD1221-GR transistor can have a current gain of 150 to 300. The gain of the 2SD1221 will be in the range from 60 to 300, for the 2SD1221-O it will be in the range from 60 to 120, for the 2SD1221-Y it will be in the range from 100 to 200.Sometimes the "2S" prefix is not marked on the package - the 2SD1221-GR might only be marked "D1221-GR".The BDP949 (SOT-223) and FZT692B (SOT-223) is the SMD version of the 2SD1221-GR transistor. These transistors are of the same type, have similar parameters and are designed for surface mounting.You can replace the 2SD1221-GR with the KTC2020D or KTC2020D-GR.