Dual 20 W BTL power amplifier# AN7190NK Technical Documentation
## 1. Application Scenarios
### Typical Use Cases
The AN7190NK is a dual-channel audio power amplifier IC primarily designed for audio amplification applications requiring moderate power output. Typical implementations include:
- Stereo Audio Systems : Dual-channel amplification for left and right audio channels in consumer audio equipment
- Portable Audio Devices : Battery-powered applications due to its moderate power consumption and thermal characteristics
- Automotive Audio Systems : In-car entertainment systems where space constraints and thermal management are critical
- Television Audio : Built-in TV speaker amplification where component count and PCB space are limited
- Computer Multimedia : PC speaker systems and multimedia audio applications
### Industry Applications
Consumer Electronics
- Home theater systems and soundbars
- Portable Bluetooth speakers
- Gaming console audio subsystems
- Smart home device audio output stages
Automotive Sector
- Head unit audio amplification
- Rear-seat entertainment systems
- Factory-installed speaker systems
Professional Audio
- Small venue PA systems
- Conference room audio
- Background music systems
### Practical Advantages
Strengths:
- Compact Package : NK package offers good thermal performance in minimal footprint
- Dual-Channel Integration : Reduces component count and board space requirements
- Moderate Power Handling : Suitable for applications requiring 10-20W per channel
- Thermal Protection : Built-in thermal shutdown prevents damage during overload conditions
- Wide Supply Range : Operates from single supply voltages typically between 12V-24V
Limitations:
- Power Output : Limited to moderate power applications (not suitable for high-power systems)
- Heat Dissipation : Requires proper thermal management at higher power levels
- Frequency Response : Optimized for audio band, not suitable for RF applications
- External Component Dependency : Performance depends on proper selection of external passive components
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Thermal Management Issues
- Pitfall : Inadequate heat sinking leading to thermal shutdown
- Solution : Implement proper PCB copper pours for heat dissipation, consider external heatsink for high-power applications
Power Supply Decoupling
- Pitfall : Insufficient decoupling causing oscillation and noise
- Solution : Use recommended capacitor values (typically 100µF electrolytic + 100nF ceramic) placed close to supply pins
Grounding Problems
- Pitfall : Poor ground layout introducing hum and noise
- Solution : Implement star grounding, separate analog and power grounds, use ground planes
Input Signal Handling
- Pitfall : DC offset at inputs causing output saturation
- Solution : Include input coupling capacitors and proper biasing networks
### Compatibility Issues
With Digital Components
- Microcontrollers : Ensure proper level shifting if digital control is implemented
- Digital Signal Processors : Match impedance and signal levels for optimal interface
With Passive Components
- Capacitors : Use low-ESR types for decoupling, audio-grade for signal path
- Resistors : 1% tolerance metal film recommended for gain-setting networks
Power Supply Compatibility
- Switching Regulators : May introduce switching noise; additional filtering required
- Linear Regulators : Preferred for noise-sensitive applications
### PCB Layout Recommendations
Power Supply Routing
- Use wide traces for power supply lines (minimum 20-30 mil width)
- Place decoupling capacitors within 5mm of supply pins
- Implement separate power and signal ground planes
Thermal Management
- Use generous copper pours connected to thermal pad
- Multiple vias under thermal pad to bottom layer for improved heat dissipation
- Consider thermal relief patterns for soldering
Signal Integrity
- Keep input traces short and away from power lines
- Use ground shielding for sensitive input
