The **2SC4635** is a high-voltage NPN epitaxial planar silicon transistor. It is primarily designed for high-definition color display applications, specifically for video output stages. --- ## 1. Key Specifications The following table outlines the absolute maximum ratings and electrical characteristics for the 2SC4635 (specifically the common "T" or "S" rank variants). | Parameter | Symbol | Rating | Unit | | :--- | :--- | :--- | :--- | | **Collector-to-Base Voltage** | $V_{CBO}$ | 120 | V | | **Collector-to-Emitter Voltage** | $V_{CEO}$ | 120 | V | | **Emitter-to-Base Voltage** | $V_{EBO}$ | 4 | V | | **Collector Current (DC)** | $I_C$ | 50 | mA | | **Collector Dissipation** | $P_C$ | 1.2 / 5.0* | W | | **Junction Temperature** | $T_j$ | 150 | °C | | **Gain-Bandwidth Product** | $f_T$ | 600 (typ) | MHz | *\*Note: 1.2W in free air, 5.0W with an appropriate heat sink.* --- ## 2. Main Features * **High Speed:** It possesses a very high gain-bandwidth product ($f_T$) of approximately 600 MHz, making it ideal for high-speed switching and video amplification. * **High Voltage:** With a $V_{CEO}$ of 120V, it can handle the high-swing signals required in CRT (Cathode Ray Tube) or high-voltage driver circuits. * **Low Capacitance:** It features a small reverse transfer capacitance ($C_{re} \approx 1.2 pF$), which reduces signal distortion at high frequencies. * **Complementary Pair:** It is often used alongside the **2SA1767** (its PNP counterpart) for push-pull amplifier configurations. --- ## 3. Package and Pinout The 2SC4635 is typically found in the **TO-126ML** (or similar slim-style) package, which allows for easy mounting to heat sinks. ### Pin Configuration 1. **Emitter (E):** The source of carriers. 2. **Collector (C):** Connected to the load or high voltage. 3. **Base (B):** The control input. --- ## 4. Common Applications * **Video Output:** High-definition CRT monitors and television sets. * **High-Frequency Amplification:** General-purpose wideband amplifiers. * **Driver Circuits:** High-speed, high-voltage switching in industrial equipment.