Compact and lightweight, High breakdown voltage, Surface mounting type# EE25NUXL Technical Documentation
## 1. Application Scenarios (45%)
### Typical Use Cases
The EE25NUXL is a high-frequency ferrite core transformer primarily employed in switch-mode power supplies (SMPS) operating at frequencies between 100 kHz and 500 kHz. Common implementations include:
- Forward Converters : Utilized in medium-power applications (50W-200W) where single-ended topologies are preferred
- Flyback Converters : Suitable for isolated power supplies requiring multiple output voltages
- DC-DC Converters : Employed in intermediate bus architectures for telecommunications equipment
- Gate Drive Transformers : Provides isolated gate driving for power MOSFETs and IGBTs in motor control circuits
### Industry Applications
Telecommunications Infrastructure
- Base station power supplies requiring high isolation voltages (up to 4kV)
- Network equipment power modules with multiple output rails
- Fiber optic transceiver power conditioning circuits
Industrial Automation
- PLC (Programmable Logic Controller) power subsystems
- Motor drive isolation circuits
- Industrial sensor power isolation
Consumer Electronics
- LCD/LED television power supplies
- Gaming console power adapters
- High-end audio amplifier power stages
Medical Equipment
- Patient monitoring devices requiring medical-grade isolation
- Portable medical instrument power supplies
### Practical Advantages and Limitations
Advantages:
- High Saturation Flux Density : 510 mT at 100°C enables compact designs
- Low Core Loss : < 600 mW/cm³ at 100 kHz, 200 mT reduces thermal management requirements
- Excellent Temperature Stability : Operating range -40°C to +125°C
- Good EMI Performance : Closed magnetic structure minimizes electromagnetic interference
- High Permeability : Initial permeability of 2300±25% provides good coupling efficiency
Limitations:
- Frequency Limitations : Performance degrades significantly above 500 kHz
- Size Constraints : EE25 footprint may be too large for ultra-compact designs
- Cost Considerations : More expensive than EFD cores in high-volume consumer applications
- Saturation Risk : Requires careful calculation of primary turns to prevent saturation at high currents
## 2. Design Considerations (35%)
### Common Design Pitfalls and Solutions
Pitfall 1: Core Saturation at High Temperature
- Problem : Reduced saturation flux density at elevated temperatures
- Solution : Derate maximum flux density to 350 mT for designs operating above 85°C
Pitfall 2: Excessive Winding Losses
- Problem : High-frequency skin effect increases AC resistance
- Solution : Use Litz wire for frequencies above 200 kHz or implement parallel strands
Pitfall 3: Insufficient Creepage Distance
- Problem : Violation of safety standards for reinforced insulation
- Solution : Maintain minimum 8mm creepage distance between primary and secondary windings
Pitfall 4: Thermal Runaway
- Problem : Core losses increasing with temperature creating positive feedback
- Solution : Implement thermal protection circuits and ensure adequate ventilation
### Compatibility Issues with Other Components
Semiconductor Compatibility
- MOSFETs : Compatible with most 600V MOSFETs in flyback configurations
- Controllers : Works well with UC384x, LT124x series PWM controllers
- Rectifiers : Requires fast recovery diodes (trr < 75ns) for secondary rectification
Passive Component Interactions
- Output Capacitors : Low ESR capacitors required to handle high ripple currents
- Input Filters : Common-mode chokes may be needed to meet EMI standards
- Snubber Networks : RCD snubbers essential for suppressing voltage spikes
### PCB Layout Recommendations
Critical Layout Practices
- Placement : Position transformer away from heat-sensitive components
- Routing
