TRANSILS# Technical Documentation: 15KE68ARL TVS Diode
Manufacturer : MOT (Motorola/ON Semiconductor)
Component Type : Uni-directional Transient Voltage Suppressor Diode
## 1. Application Scenarios
### Typical Use Cases
The 15KE68ARL is primarily employed for transient voltage protection in electronic circuits, specifically designed to clamp voltage spikes and suppress electrostatic discharge (ESD) events. Typical applications include:
- Power Supply Protection : Safeguarding DC power lines from voltage transients induced by lightning strikes, inductive load switching, or power supply fluctuations
- Communication Interfaces : Protecting RS-232, RS-485, and Ethernet ports from voltage surges
- Automotive Electronics : Shielding automotive control units (ECUs) from load dump transients and switching spikes
- Industrial Control Systems : Securing PLCs, sensors, and actuators from industrial noise and voltage transients
### Industry Applications
- Telecommunications : Base station equipment, network switches, and communication modules
- Automotive : Engine control modules, infotainment systems, and body control modules
- Consumer Electronics : Power adapters, set-top boxes, and gaming consoles
- Industrial Automation : Motor drives, power distribution systems, and measurement equipment
- Renewable Energy : Solar inverters and wind turbine control systems
### Practical Advantages and Limitations
Advantages:
- Rapid Response Time : Responds to transients within picoseconds, significantly faster than MOVs or gas discharge tubes
- High Peak Pulse Power : Capable of handling 1500W (15KW for 1ms) transient events
- Low Clamping Voltage : Provides effective protection by limiting voltage to safe levels
- Reliable Performance : Maintains consistent characteristics over numerous surge events
- Compact Package : DO-201AD package offers robust protection in minimal space
Limitations:
- Energy Handling : Limited compared to some competing technologies; not suitable for sustained overvoltage conditions
- Capacitance Effects : May introduce signal integrity issues in high-frequency applications (>100MHz)
- Uni-directional Nature : Only protects against positive voltage transients; requires additional components for bidirectional protection
- Thermal Considerations : Requires proper heat dissipation during repeated surge events
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Pitfall 1: Improper Voltage Rating Selection
- Issue : Selecting TVS with standoff voltage too close to operating voltage
- Solution : Ensure standoff voltage (58.1V) exceeds maximum normal operating voltage by 10-20%
Pitfall 2: Inadequate Current Handling
- Issue : Underestimating peak pulse current requirements
- Solution : Calculate maximum expected surge current and verify 15KE68ARL's 26.1A peak pulse current rating suffices
Pitfall 3: Poor Placement
- Issue : Placing TVS diode too far from protected component
- Solution : Position as close as possible to the point of entry for transients, minimizing trace inductance
### Compatibility Issues with Other Components
Power Supply Compatibility:
- Compatible with most DC power supplies up to 58V
- May require series resistors when used with high-impedance sources
Microcontroller/Processor Interfaces:
- Ensure clamping voltage (93.6V) doesn't exceed protected IC's absolute maximum ratings
- Consider adding series resistors for current limiting in sensitive applications
Communication Line Considerations:
- Verify capacitance (≤50pF) doesn't degrade signal integrity in high-speed interfaces
- For bidirectional protection, pair with complementary uni-directional TVS or use bidirectional devices
### PCB Layout Recommendations
Placement Strategy:
- Position immediately after connectors or entry points
- Minimize trace length between TVS and
