TRANSILS# 15KE68CARL TVS Diode Technical Documentation
## 1. Application Scenarios
### Typical Use Cases
The 15KE68CARL is a bidirectional Transient Voltage Suppression (TVS) diode designed for robust overvoltage protection in electronic circuits. Typical applications include:
- ESD Protection : Safeguards sensitive ICs from electrostatic discharge events up to 30kV
- Lightning/Surge Protection : Provides secondary protection against induced lightning surges in communication lines
- Inductive Load Switching : Protects against voltage spikes from relay coils, motor windings, and solenoid valves
- Power Supply Protection : Secures DC power lines against transient overvoltage conditions
- Automotive Load Dump : Handles voltage transients in automotive 12V/24V systems
### Industry Applications
- Telecommunications : Protects DSL modems, routers, and base station equipment
- Automotive Electronics : ECU protection, CAN bus lines, and infotainment systems
- Industrial Control : PLC I/O modules, sensor interfaces, and motor drives
- Consumer Electronics : USB ports, HDMI interfaces, and power input circuits
- Medical Devices : Patient monitoring equipment and diagnostic instruments
### Practical Advantages and Limitations
Advantages:
- Fast Response Time : Reacts to transients in picosecond range (<1ns)
- High Surge Capability : Withstands 10/1000μs surge pulses up to 86.7A
- Bidirectional Operation : Protects against both positive and negative transients
- Low Clamping Ratio : Vc = 110V maximum at 86.7A surge current
- Compact DO-201 Package : Space-efficient design for PCB mounting
Limitations:
- Limited Energy Absorption : Not suitable for sustained overvoltage conditions
- Parasitic Capacitance : ~150pF may affect high-frequency signal integrity (>100MHz)
- Standoff Voltage : 58.1V limits use in higher voltage systems
- Thermal Considerations : Requires proper heat dissipation during repeated transients
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Pitfall 1: Incorrect Voltage Rating Selection
- Problem : Selecting TVS with standoff voltage too close to operating voltage
- Solution : Ensure Vrwm (58.1V) exceeds maximum normal operating voltage by 10-20%
Pitfall 2: Inadequate Current Handling
- Problem : Underestimating surge current requirements
- Solution : Calculate worst-case surge current and verify Ipp (86.7A) provides sufficient margin
Pitfall 3: Poor Placement
- Problem : TVS located too far from protected component
- Solution : Place within 1-2cm of protected interface with minimal trace inductance
### Compatibility Issues with Other Components
Microcontrollers and ASICs:
- Ensure clamping voltage (110V max) doesn't exceed protected device absolute maximum ratings
- Consider adding series resistance for current limiting during sustained overvoltage
Power Supplies:
- Compatible with switching regulators up to 48V systems
- May require additional filtering when used with sensitive analog circuits
Communication Interfaces:
- Capacitance (150pF) may affect signal integrity in high-speed digital lines (>100Mbps)
- For high-speed applications, consider lower capacitance TVS alternatives
### PCB Layout Recommendations
Placement Strategy:
- Position immediately adjacent to protected connector or component
- Minimize trace length between TVS and protected circuit (<25mm ideal)
Routing Guidelines:
- Use wide traces (≥1mm) to handle surge currents
- Avoid vias in surge current path when possible
- Implement ground pour directly under TVS for thermal management
Thermal Management
