Silicon PNP Epitaxial Planar Transistor(TV Vertical Output, Audio Output Driver and General Purpose) # Technical Documentation: 2SA1668 PNP Transistor
Manufacturer : SANKEN
Document Version : 1.0
Last Updated : [Current Date]
## 1. Application Scenarios
### Typical Use Cases
The 2SA1668 is a high-voltage PNP bipolar junction transistor (BJT) primarily employed in power management and amplification circuits. Key applications include:
- Series Pass Elements in linear voltage regulators (5-60V systems)
- Audio Output Stages in complementary symmetry amplifiers (up to 80W systems)
- Driver Stages for larger power transistors in push-pull configurations
- Switch Mode Power Supplies as switching elements in flyback converters
- Motor Drive Circuits for small to medium DC motor control
### Industry Applications
- Consumer Electronics : Audio amplifiers, television vertical deflection circuits
- Industrial Control : Power supply units, motor controllers
- Telecommunications : Line drivers, power management circuits
- Automotive Electronics : Voltage regulators (non-critical systems)
### Practical Advantages and Limitations
Advantages:
- High collector-emitter voltage rating (160V) suitable for line-operated equipment
- Excellent DC current gain linearity (hFE 60-200 at 1A)
- Low saturation voltage (VCE(sat) = 1.5V max @ IC=1.5A)
- Robust TO-220 package with isolated tab for simplified heatsinking
- Wide operating temperature range (-55°C to +150°C)
Limitations:
- Moderate switching speed (fT=20MHz) limits high-frequency applications
- Requires careful thermal management at maximum current ratings
- PNP configuration may complicate circuit design compared to NPN alternatives
- Higher saturation voltage than modern MOSFET equivalents
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Thermal Runaway
- Problem : Increasing temperature reduces VBE, causing current hogging
- Solution : Implement emitter degeneration resistors (0.1-0.5Ω)
- Mitigation : Use adequate heatsinking (θJA < 62.5°C/W for full power)
Secondary Breakdown
- Problem : Localized heating at high VCE and IC combinations
- Solution : Operate within Safe Operating Area (SOA) boundaries
- Implementation : Use SOA curves from datasheet for all operating conditions
Storage Time Issues
- Problem : Slow turn-off in switching applications
- Solution : Implement Baker clamp circuits or speed-up capacitors
- Alternative : Use negative base drive for faster switching
### Compatibility Issues with Other Components
Driver Circuit Compatibility
- Requires adequate base drive current (IB ≈ IC/10 for saturation)
- Compatible with common driver ICs (ULN2003, MC1413)
- May require level shifting when interfacing with CMOS logic
Complementary Pairing
- Optimal pairing: 2SC4381 (NPN complement)
- Mismatch considerations: Check hFE matching for push-pull stages
- Thermal tracking: Ensure complementary devices share thermal environment
### PCB Layout Recommendations
Power Handling Layout
- Use 50-100mil traces for collector and emitter connections
- Implement star grounding for high-current paths
- Place decoupling capacitors (100nF ceramic) within 10mm of device pins
Thermal Management
- Provide adequate copper area (≥ 2in² for 1W dissipation)
- Use thermal vias when mounting to heatsinks
- Maintain 3mm clearance around package for air circulation
EMI Considerations
- Keep high di/dt paths away from sensitive analog circuits
- Use ground planes for noise reduction
- Implement snubber circuits (RC networks) for inductive loads
## 3. Technical Specifications
### Key Parameter Explanations
Absolute Maximum Ratings
