BI-DIRECTIONAL GLASS PASSIVATED JUNCTION TRANSIENT VOLTAGE SUPPRESSOR 1500 WATTS, 6.8 THRU 200 VOLTS# Technical Documentation: 15SMC68CA Transient Voltage Suppressor (TVS)
Manufacturer : VISHAY
Component Type : 15kW Transient Voltage Suppressor Diode
Document Version : 1.0
Date : October 2023
## 1. Application Scenarios
### Typical Use Cases
The 15SMC68CA is a 15kW surface-mount transient voltage suppressor designed for high-power surge protection in demanding applications. Typical deployment scenarios include:
Primary Protection Applications:
- Direct lightning surge protection in telecommunications equipment
- Industrial motor drive systems requiring robust overvoltage protection
- Power supply input stages in harsh electrical environments
- Automotive electronic control units (ECUs) for load dump protection
Critical Infrastructure Protection:
- Telecom base station power and signal lines
- Industrial PLC systems exposed to voltage transients
- Renewable energy systems (solar/wind inverter protection)
- Medical equipment power input protection
### Industry Applications
Telecommunications:
- Protects sensitive RF equipment from induced lightning surges
- Base station power and data line protection
- DSL/POTS line interface circuits
- Meets GR-1089 and ITU-T K.20/K.21 surge standards
Industrial Automation:
- PLC I/O module protection (24V/48V systems)
- Motor drive input stage surge suppression
- Process control instrumentation
- Compliant with IEC 61000-4-5 surge requirements
Automotive Electronics:
- Load dump protection (ISO 7637-2 compliant)
- ECU power input protection
- 12V/24V automotive bus systems
- Electric vehicle charging systems
Power Systems:
- Switch-mode power supply input protection
- UPS system surge suppression
- Renewable energy converter protection
### Practical Advantages and Limitations
Advantages:
- High Surge Capability : 15kW peak pulse power (8/20μs waveform)
- Low Clamping Ratio : Excellent voltage limiting characteristics
- Fast Response Time : Typically <1.0ps response to transients
- Surface Mount Package : SMC (DO-214AB) package for automated assembly
- High Temperature Operation : -65°C to +150°C operating range
- AEC-Q101 Qualified : Suitable for automotive applications
Limitations:
- Package Size : SMC package requires adequate PCB space
- Thermal Management : Requires proper heat sinking for repeated surges
- Voltage Margin : Requires careful selection to avoid normal operation near breakdown
- Cost Consideration : Higher cost compared to lower power TVS devices
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Pitfall 1: Inadequate Voltage Margin
- Problem : Selecting VRWM too close to operating voltage
- Solution : Maintain 10-20% margin above maximum operating voltage
Pitfall 2: Poor Thermal Management
- Problem : Repeated surges causing thermal runaway
- Solution : Implement adequate copper pour for heat dissipation
Pitfall 3: Incorrect Placement
- Problem : TVS located too far from protected circuit
- Solution : Place within 1-2 cm of protection point with minimal trace inductance
Pitfall 4: Grounding Issues
- Problem : High-impedance ground connection reducing effectiveness
- Solution : Use low-inductance ground path with multiple vias
### Compatibility Issues with Other Components
With Microcontrollers/Digital ICs:
- Ensure VCLAMP is below absolute maximum ratings of protected devices
- Consider adding series resistance for current limiting
With Power Supplies:
- Coordinate with input filters to avoid oscillation
- Consider inrush current compatibility
With Other Protection Devices:
- May be used in coordination with gas discharge tubes (
