The **2SA684L-X-AB3-R** is a high-performance PNP epitaxial silicon transistor. It is widely utilized in audio frequency power amplification and general-purpose switching applications. --- ### 1. General Specifications Below is a breakdown of the primary characteristics for this specific part number: | Parameter | Description | | :--- | :--- | | **Polarity** | PNP | | **Material** | Silicon (Epitaxial) | | **Package Type** | SOT-89 (Standard for surface mount power devices) | | **Application** | Low frequency power amplifier, complementary to 2SC1213 | --- ### 2. Absolute Maximum Ratings These values represent the limits the device can handle at $T_a = 25^\circ C$: | Symbol | Parameter | Rating | Unit | | :--- | :--- | :--- | :--- | | $V_{CBO}$ | Collector-Base Voltage | -60 | V | | $V_{CEO}$ | Collector-Emitter Voltage | -50 | V | | $V_{EBO}$ | Emitter-Base Voltage | -5 | V | | $I_C$ | Collector Current (DC) | -1 | A | | $P_C$ | Collector Power Dissipation | 500 | mW | | $T_J$ | Junction Temperature | +150 | $^\circ C$ | --- ### 3. Electrical Characteristics Key performance metrics that define how the transistor operates within a circuit: * **DC Current Gain ($h_{FE}$):** Typically ranges between 85 to 340 (The "X" in the part number often denotes a specific gain rank). * **Collector-Emitter Saturation Voltage ($V_{CE(sat)}$):** Usually around -0.7V max at $I_C = -500mA$, indicating efficient switching. * **Transition Frequency ($f_T$):** Approximately 200 MHz, making it suitable for high-speed switching and high-frequency audio stages. --- ### 4. Part Number Breakdown The suffixing in **2SA684L-X-AB3-R** provides specific manufacturing details: * **2SA684:** The base model (PNP, High Frequency). * **L:** Often denotes Lead-free or specific Low-voltage characteristics. * **X:** The $h_{FE}$ (gain) classification rank. * **AB3:** Refers to the **SOT-89** package style in many manufacturer catalogs (like UTC). * **R:** Tape and Reel packaging. --- ### 5. Application Circuit Example (Simple PNP Switch) To use this in a circuit to switch a small load: ```cpp // Basic schematic logic [VCC] --- [Load] --- [Collector (C)] | [Input] --- [Resistor] --- [Base (B)] | [GND] ----------------- [Emitter (E)] ``` *Note: Since it is PNP, the load is usually placed between the Collector and the negative rail/ground if the Emitter is tied to VCC.* ---