ZTX551 Bipolar Transistor

• Type: PNP
• Collector-Emitter Voltage, max: -60 V
• Collector-Base Voltage, max: -80 V
• Emitter-Base Voltage, max: -5 V
• Collector Current − Continuous, max: -1 A
• Collector Dissipation: 1 W
• DC Current Gain (h_fe): 50 to 150
• Transition Frequency, min: 150 MHz
• Operating and Storage Junction Temperature Range: -55 to +200 °C
• Package: TO-92

The ZTX551 is manufactured in a plastic TO-92 case. When looking at the flat side with the leads pointed downward, the three leads emerging from the transistor are, from left to right, the emitter, base, and collector leads.
Here is an image showing the pin diagram of this transistor.The FMMT551 (SOT-23) is the SMD version of the ZTX551 transistor. These transistors are of the same type, have similar parameters and are designed for surface mounting.You can replace the ZTX551 with the BC527, BC528, MPS4354, MPS4356, ZTX552, ZTX553 or ZTX554.