The **2SC5548A** is a high-speed, high-voltage NPN silicon epitaxial transistor primarily designed for high-resolution display applications, such as horizontal deflection output in monitors and televisions. --- ### 1. Key Technical Specifications The following table highlights the absolute maximum ratings and electrical characteristics of the 2SC5548A: | Parameter | Symbol | Rating | Unit | | :--- | :--- | :--- | :--- | | Collector-Base Voltage | $V_{CBO}$ | 1500 | V | | Collector-Emitter Voltage | $V_{CEO}$ | 600 | V | | Emitter-Base Voltage | $V_{EBO}$ | 5 | V | | Collector Current (DC) | $I_C$ | 10 | A | | Collector Current (Pulse) | $I_{CP}$ | 20 | A | | Total Power Dissipation ($T_c = 25^\circ C$) | $P_D$ | 50 | W | | Junction Temperature | $T_j$ | 150 | $^\circ$C | --- ### 2. Physical and Structural Characteristics * **Package Type:** Usually found in a **TO-3PF** or similar isolated plastic package. This design allows for easier mounting to heat sinks without the need for additional insulating washers. * **Polarity:** **NPN** (Negative-Positive-Negative). * **Built-in Features:** Some variants may include a built-in damper diode or a base-emitter resistor, though the standard "A" suffix often denotes high-speed switching improvements. --- ### 3. Primary Applications Because of its high voltage tolerance and fast switching speeds, this transistor is specialized for: 1. **Horizontal Deflection Output:** Used in CRT monitors and high-definition televisions to control the electron beam sweep. 2. **Switching Power Supplies:** High-voltage DC-DC converters. 3. **High-Voltage Inverters:** Industrial equipment requiring robust voltage regulation. --- ### 4. Typical Circuit Pinout Looking at the front of the transistor (the side with the text), the pins are typically arranged as follows: | Pin Number | Terminal Name | Function | | :--- | :--- | :--- | | 1 | **Base** | Controls the current between collector and emitter. | | 2 | **Collector** | Connected to the high-voltage load. | | 3 | **Emitter** | Usually connected to the common ground or return. | --- ### 5. Equivalent/Replacement Parts If the 2SC5548A is unavailable, the following parts are often considered as functional equivalents (subject to datasheet verification of the specific circuit requirements): * **2SC5584** * **KSC5502** * **BU2520DX** (Often used in similar deflection circuits) ---