SS8550 Transistor Y2 PNP 25V 1.5A 1500mW SOT-23

SS8550 Y2 PNP Transistor 25V 1.5A 1500mW SOT-23 is a high-current, low-voltage PNP bi-polar junction transistor (BJT) widely used for amplification and switching applications in compact electronic designs. This transistor features a complementary NPN counterpart, the SS8050, offering excellent design flexibility. Encased in the tiny surface-mount SOT-23 package with a ‘Y2’ marking, the SS8550 allows designers to save significant PCB space. Consequently, it becomes an ideal choice for portable devices and high-density boards where efficient current control is essential. Furthermore, its high current rating (1.5 A) and excellent gain make it a reliable workhorse for driving medium-power loads.

Key Features:

• High Collector Current: Handles a continuous collector current (I_C) up to −1.5 A, suitable for driving LEDs, relays, and small motors.
• High Power Dissipation: Offers a generous collector power dissipation (P_C) of up to 1.5 W (when properly mounted on a large PCB), enabling it to manage moderate power applications.
• Compact Surface Mount: Utilizes the small SOT-23 package, therefore minimizing board footprint in size-constrained products.
• High DC Current Gain (h_FE): Features a high gain, typically ranging from 120 to 400 (depending on the rank), which provides efficient switching from low base currents.
• Complementary Pair: Serves as the PNP complement to the popular SS8050 (NPN), greatly simplifying push-pull amplifier and driver stage design.

Technical Specifications:

• Transistor Polarity: PNP (Negative-Positive-Negative)
• Max Collector-Emitter Voltage (V_CEO): −25 V
• Max Collector-Base Voltage (V_CBO): −40 V
• Max Emitter-Base Voltage (V_EBO): −5 V
• Max Collector Current (I_C): −1.5 A
• Max Collector Power Dissipation (P_C): 300 mW (Free Air) / 1.5 W (On appropriate PCB)
• Transition Frequency (f_T): Typically 100 MHz
• Marking Code: Y2
• Operating Junction Temperature (T_J): Up to 150°C

Mechanical Specifications:

• Package Type: SOT-23 (Small Outline Transistor, Surface Mount Device)
• Mounting: Surface Mount Technology (SMT)
• Pin Configuration: Emitter-Base-Collector (E-B-C)
• Material: Silicon Epitaxial Planar Transistor

Dimensions:

• Body Length (A): ≈ 2.9 mm
• Body Width (B): ≈ 1.3 mm
• Body Height (C): ≈ 1.1 mm
• Pitch (e): 1.9 mm (Pin 1 to Pin 2/3)
• Lead Finish: Lead-free plating (typically Sn)

Pinout and Wiring:

• Pin 1 (Base): Controls the current flow between the Collector and Emitter. Apply a low/negative voltage relative to the Emitter to turn the transistor ON.
• Pin 2 (Emitter): Connect the Emitter to the positive supply voltage in most switching or amplifier circuits.
• Pin 3 (Collector): Connect the Collector to the load you want to control (e.g., LED, relay coil).
• Wiring Note: Always apply a current-limiting resistor to the Base pin to prevent damage to the transistor and the driving circuit. Remember, the pinout for SOT-23 devices can vary between manufacturers, so always confirm with the specific datasheet.

Datasheet Reference:

• Download ON Semiconductor SS8550 Datasheet (TO-92, functionally similar to SOT-23)

Commonly Used in:

• Portable Consumer Electronics: Ideal for power management and switching in devices like smartphones, digital cameras, and audio equipment.
• LED and Display Drivers: Effectively handles the current required to drive medium-power LED strips and backlights.
• Signal Amplification: Utilized in audio amplification stages and pre-amplifiers where high current gain is beneficial.

Applications:

• Switching Circuits: You can use the SS8550 to switch loads up to 1.5 A via a low-current digital signal.
• Class B Amplifier Output Stage: Paired with the SS8050, it forms a common complementary output stage in push-pull audio amplifiers.
• Voltage Regulation: Provides current amplification in various linear and low-dropout (LDO) regulator circuits.

Equivalent Models:

• S8550 (TO-92): The through-hole version of the same transistor, offering similar electrical characteristics.
• 2N2907A (Similar): A commonly available PNP transistor with comparable voltage ratings, however, its current capability may differ slightly.
• BC557: A lower-current general-purpose PNP transistor, suitable for lighter-duty signal applications.
• SS8050 (NPN Complement): The NPN counterpart to the SS8550, essential for push-pull configurations.

Package Includes:

• 1 x SS8550 Y2 PNP Transistor 25V 1.5A 1500mW SOT-23