Part Number : MMBT5551
Function : NPN small signal surface mount transistor.
Package : SOT-23 Type
Maker : Diodes Incorporated.
Pinouts : 
Features
• Epitaxial Planar Die Construction
• Complementary PNP Type Available (MMBT5401)
• Ideal for Low Power Amplification and Switching
• Lead, Halogen and Antimony Free, RoHS Compliant
• "Green" Device
Absolute maximum ratings ( Ta=25°C )
1. Collector to Base Voltage : Vcbo = 180 V
2. Collector to Emitter Voltage : Vceo = 160 V
3. Emitter to Base Voltage : Vebo = 6 V
4. Collector Current : Ic = 600 mA
Mechanical Data
• Case: SOT-23
• Case Material: Molded Plastic. UL Flammability Classification Rating 94V-0
• Moisture Sensitivity: Level 1 per J-STD-020D
• Terminal Connections: See Diagram
• Terminals: Solderable per MIL-STD-202, Method 208
• Lead Free Plating (Matte Tin Finish annealed over Alloy 42 leadframe).
• Weight: 0.008 grams (approximate)
Applications :
Ideal for medium power application and switching
Datasheet PDF Download :
Others datasheet of same file : MMBT-5551, MMBT5551-7-F