The **AN753** is an integrated circuit (IC) primarily designed as a **Vertical Deflection Output** controller for televisions and monitors. It is commonly used in CRT (Cathode Ray Tube) displays to control the vertical scanning of the electron beam. --- ### 1. Key Technical Specifications The AN753 is manufactured by Panasonic (formerly Matsushita). Below are the typical electrical characteristics: | Parameter | Value (Typical) | | :--- | :--- | | **Function** | Vertical Deflection Output | | **Supply Voltage ($V_{CC}$)** | 24V - 30V | | **Output Current** | Up to 1.5A - 2.0A (Peak) | | **Package Type** | SIL-7 (Single In-Line 7-pin) | | **Operating Temperature** | -20°C to +75°C | --- ### 2. Internal Block Composition The IC contains several functional stages to handle the high-current demands of a deflection coil: 1. **Power Amplifier:** Drives the vertical deflection yoke. 2. **Pump-up Circuit:** Efficiently doubles the voltage during the vertical retrace period to ensure a fast reset of the electron beam. 3. **Thermal Protection:** Built-in shutdown mechanism to prevent the chip from burning out due to overheating. 4. **Current Limiter:** Protects the IC and the deflection yoke from over-current conditions. --- ### 3. Pin Configuration (Typical SIL-7) | Pin No. | Function | Description | | :--- | :--- | :--- | | 1 | **$V_{CC}$1** | Control circuit power supply | | 2 | **Vertical Input** | Receives the sawtooth wave signal from the processor | | 3 | **Pump-up Out** | Connection for the flyback capacitor | | 4 | **GND** | Ground | | 5 | **Output** | Connection to the Vertical Deflection Yoke | | 6 | **$V_{CC}$2** | Output stage power supply | | 7 | **Feedback** | Error correction and linearity control | --- ### 4. Common Applications and Troubleshooting * **Usage:** Found in small-to-medium sized color TVs and CRT computer monitors. * **Common Failure Symptoms:** * **Horizontal Line:** A single bright line across the center of the screen (indicates total vertical collapse). * **Vertical Jitter:** Shaking image caused by unstable power supply to the IC. * **Overheating:** If the heatsink is loose or the supply voltage is too high, the IC will shut down. --- ### 5. Implementation Example (Schematic Logic) In a typical circuit, the input signal is a low-voltage sawtooth wave. The AN753 amplifies this into a high-current signal capable of driving the electromagnetic coils around the neck of the CRT. ```c // Concept of Vertical Sync Control Input (Sawtooth Wave) -> AN753 (Power Amp) -> Deflection Yoke (Magnetic Field) ```