TV VERTICAL DEFLECTION OUTPUT CIRCUIT# AN5520 Technical Documentation
## 1. Application Scenarios
### Typical Use Cases
The AN5520 is a vertical deflection output IC primarily designed for CRT display systems . Its main applications include:
- Television vertical deflection circuits - Provides the necessary sawtooth waveform to control vertical scanning of electron beams
- Monitor deflection systems - Used in computer monitors and industrial displays employing CRT technology
- Oscilloscope vertical amplifiers - Suitable for test and measurement equipment requiring precise vertical deflection control
### Industry Applications
- Consumer Electronics : Traditional CRT televisions and video monitors
- Industrial Equipment : Legacy industrial monitors and control panel displays
- Medical Devices : Older medical imaging displays and monitoring equipment
- Broadcast Equipment : Studio monitors and broadcast reference displays
### Practical Advantages
- Integrated Solution : Combines vertical oscillator, amplifier, and output stage in single package
- Thermal Protection : Built-in thermal shutdown prevents damage from overheating
- High Voltage Tolerance : Designed to handle the high voltage requirements of CRT deflection systems
- Reliable Performance : Proven reliability in mass production applications
### Limitations
- Legacy Technology : Limited relevance in modern flat-panel display systems
- Power Consumption : Higher power requirements compared to modern display ICs
- Component Availability : Becoming increasingly difficult to source as CRT technology phases out
- Size Constraints : Requires larger heat sinking than contemporary display drivers
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Thermal Management Issues
- Pitfall : Inadequate heat sinking leading to thermal shutdown
- Solution : Implement proper heat sinking with thermal compound and ensure adequate airflow
Oscillation Stability
- Pitfall : Unstable vertical oscillation causing display jitter
- Solution : Use recommended capacitor values for timing circuits and ensure stable power supply
Output Stage Protection
- Pitfall : Flyback voltage spikes damaging output transistors
- Solution : Incorporate proper snubber circuits and voltage clamping components
### Compatibility Issues
Power Supply Requirements
- The AN5520 requires dual power supplies (+Vcc and -Vee) typically in the range of ±12V to ±24V
- Incompatible with single-supply systems without additional circuitry
Load Compatibility
- Designed specifically for vertical deflection coils with typical impedance of 5-15Ω
- Not suitable for driving other types of loads without significant modification
Timing Circuit Compatibility
- Requires external RC networks for oscillation timing
- Must be compatible with the horizontal synchronization signals from the video processor
### PCB Layout Recommendations
Power Supply Routing
- Use wide traces for power supply lines (minimum 40 mil width)
- Implement star grounding for analog and power grounds
- Place decoupling capacitors as close as possible to power pins
Thermal Management
- Provide adequate copper area for heat dissipation (minimum 2 square inches)
- Use thermal vias to transfer heat to ground plane
- Ensure component spacing for proper airflow
Signal Integrity
- Keep oscillator components close to the IC to minimize parasitic effects
- Route deflection coil connections away from sensitive analog circuits
- Implement proper shielding for high-frequency noise sources
## 3. Technical Specifications
### Key Parameter Explanations
Supply Voltage Range
- Vcc : +9V to +24V (typical +12V)
- Vee : -9V to -24V (typical -12V)
- Absolute maximum : ±27V
Output Characteristics
- Peak Output Current : 1.5A maximum
- Output Voltage Swing : Typically ±10V peak-to-peak
- Slew Rate : 15V/μs
