Single-Phase Full-Wave Motor Driver for Fan Motor # BA6428F Technical Documentation
## 1. Application Scenarios
### Typical Use Cases
The BA6428F is a 3-phase brushless DC motor driver IC primarily designed for precision motor control applications. Typical implementations include:
- Spindle motor drives for optical disc systems (CD/DVD/Blu-ray drives)
- Cooling fan controllers in computing equipment and server systems
- Precision positioning systems requiring smooth rotation control
- Small appliance motors in household and industrial equipment
### Industry Applications
Consumer Electronics:
- Optical media drives in entertainment systems
- Computer cooling systems and peripheral devices
- Home automation motor controls
Industrial Automation:
- Small robotic arm actuators
- Conveyor belt drive systems
- Precision instrument positioning mechanisms
Automotive Electronics:
- HVAC blower motor controls
- Power window and seat adjustment systems
- Fuel pump motor drivers
### Practical Advantages and Limitations
Advantages:
- Integrated design reduces external component count and board space requirements
- Built-in protection circuits including thermal shutdown and overcurrent protection
- Low standby current (typically 100μA) for power-efficient operation
- Wide operating voltage range (7V to 28V) accommodates various power supply configurations
- Hall sensor input compatibility simplifies position feedback implementation
Limitations:
- Current handling capacity limited to 1.5A peak, restricting use in high-power applications
- Package thermal constraints may require external heatsinking for continuous high-load operation
- Fixed PWM frequency limits flexibility in noise-sensitive applications
- Limited diagnostic feedback compared to modern motor driver ICs with extensive status reporting
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Pitfall 1: Inadequate Decoupling
- Issue: Motor noise coupling into power supply lines
- Solution: Implement 100nF ceramic capacitor close to VCC pin and 10μF electrolytic capacitor for bulk decoupling
Pitfall 2: Thermal Management
- Issue: Excessive junction temperature during continuous operation
- Solution:
- Ensure adequate copper pour for heat dissipation
- Consider external heatsink for applications exceeding 500mA continuous current
- Implement thermal monitoring or derating for high ambient temperatures
Pitfall 3: Ground Loop Problems
- Issue: Noise from motor currents affecting control signals
- Solution: Use star grounding technique and separate analog/digital ground planes
### Compatibility Issues
Sensor Interface:
- Compatible with Hall effect sensors with open-collector outputs
- Requires pull-up resistors (typically 10kΩ) for sensor inputs
- May require signal conditioning for sensors with different output characteristics
Microcontroller Interface:
- Direct compatibility with 3.3V and 5V logic levels
- PWM input accepts standard microcontroller outputs
- Enable/disable control compatible with GPIO pins
Power Supply Requirements:
- Requires stable 12V supply for optimal performance
- Voltage transients above 28V may damage the device
- Separate logic supply (VCC) and motor supply (VM) recommended for noise isolation
### PCB Layout Recommendations
Power Stage Layout:
- Use wide traces (minimum 2mm) for motor output pins (OUT1, OUT2, OUT3)
- Place bulk capacitors (100μF) close to VM pin
- Implement ground plane for improved thermal and noise performance
Signal Routing:
- Keep Hall sensor inputs (H1, H2, H3) away from high-current motor traces
- Route control signals (FG, RD, PWM) with proper impedance
