HY4D S8550M-D PNP 25V 1.5A SMD Transistor SOT-23

HY4D S8550M-D PNP 25V 1.5A SMD Transistor is a high-performance general-purpose transistor, optimized for compact and efficient surface-mount designs. Featuring a PNP polarity and housed in the ultra-small SOT-23 package, it’s an ideal choice for switching and amplification tasks in portable, battery-powered, and space-constrained devices. With its 1.5A collector current capability and low collector-emitter saturation voltage, the S8550M-D provides reliable performance, reduced power loss, and excellent energy efficiency across a wide range of applications.

Key Features:

• High Current Capability: Supports continuous collector current up to 1.5A, suitable for driving moderate loads like relays, LEDs, and motors.
• PNP Polarity: Functions as a high-side switch, sinking current from the load — useful in various analog and digital control circuits.
• Surface-Mount Device (SMD): Compact SOT-23 package allows dense PCB layouts, ideal for miniature electronics.
• Low Saturation Voltage (V_CE(sat)): Ensures minimal voltage drop and low power dissipation for efficient operation.
• General Purpose: Versatile for both signal amplification and power switching applications.
• High DC Current Gain (h_FE): Provides strong amplification with low base drive current requirements.

Technical Specifications:

• Type: PNP Junction Transistor (BJT)
• Collector–Base Voltage (V_CBO): 40 V
• Collector–Emitter Voltage (V_CEO): 25 V
• Emitter–Base Voltage (V_EBO): 6 V
• Collector Current (I_C): 1.5 A (Continuous)
• Power Dissipation (P_D): 300 mW (SOT-23 package)
• DC Current Gain (h_FE): Typically 100–300 (depending on grade)
• Operating Temperature Range: -55°C to +150°C

Mechanical Specifications:

• Package: SOT-23 (Small Outline Transistor)
• Mounting Style: Surface Mount Technology (SMT)
• Marking Code: HY4D (Identifies the S8550M-D model and gain group)
• Lead Finish: Lead-free (Pb-free) plating

Dimensions:

• Length: Approx. 2.9 mm
• Width: Approx. 1.3 mm
• Height: Approx. 1.0 mm (excluding leads)

Pinout and Wiring:

• Pin 1 (E): Emitter — connects to the positive supply or ground, depending on the circuit configuration.
• Pin 2 (B): Base — control terminal; apply a voltage lower than the emitter to turn ON the transistor.
• Pin 3 (C): Collector — connects to the load or power rail.
• Wiring Note: For PNP operation, the base must be pulled lower than the emitter (typically toward ground). Current flows from Emitter → Collector when the base is biased correctly.

Datasheet Reference:

• Download S8550M-D Datasheet

Commonly Used In:

• Battery-Powered Devices: Mobile phones, remote controls, portable players, and other handheld electronics.
• LED Drivers: Ideal for switching and controlling LED strips or clusters.
• Consumer Electronics: Audio amplifiers, power controllers, and low-power switching circuits.

Applications:

• Power Switching: Drives relays, solenoids, or small DC motors.
• Audio Amplification: Suitable for preamp or low-power output stages.
• Logic Level Shifting: Interfaces low-current microcontroller signals to higher-current loads.
• Voltage Regulation: Used in linear regulators and analog control loops.

Equivalent Models:

• S8550: Standard TO-92 packaged version.
• 2SA1015 / 2N3906: Other common general-purpose PNP transistors with varying voltage/current specs.
• SS8550: Equivalent SMD version available from multiple manufacturers.

Package Includes:

• 1 × HY4D S8550M-D PNP 25V 1.5A SMD Transistor (SOT-23)