R/2R Ladder Dual-In-Line Thick Film Resistor Networks # Technical Documentation: 89910R20K Fixed Inductor
Manufacturer : BI Technologies (TT Electronics)
Component Type : Wirewound Fixed Inductor
Part Number : 89910R20K
## 1. Application Scenarios
### Typical Use Cases
The 89910R20K is a 20 μH radial leaded inductor designed for moderate current applications in power electronics. Typical implementations include:
Power Supply Filtering
- Switching regulator output filtering in DC-DC converters
- Input filter circuits for reducing electromagnetic interference (EMI)
- LC filter networks in power conditioning systems
- Noise suppression in voltage regulator modules
Energy Storage Applications
- Buck/boost converter energy storage elements
- Flyback converter transformer applications
- Continuous conduction mode power factor correction circuits
Signal Processing
- RF impedance matching networks
- Analog filter circuits in audio and communication systems
- Resonant tank circuits in oscillator designs
### Industry Applications
Automotive Electronics
- Engine control unit (ECU) power filtering
- Infotainment system power management
- LED driver circuits for automotive lighting
- Sensor interface conditioning circuits
Industrial Control Systems
- PLC power supply filtering
- Motor drive noise suppression
- Industrial automation power conditioning
- Process control instrumentation
Consumer Electronics
- LCD/LED TV power management
- Set-top box power circuits
- Computer peripheral power filtering
- Battery charging circuits
Telecommunications
- Base station power systems
- Network equipment power distribution
- Telecom infrastructure power filtering
### Practical Advantages and Limitations
Advantages:
- High Q Factor : Excellent quality factor at operating frequencies (typically 40-100 at 1 MHz)
- Temperature Stability : Stable inductance across operating temperature range (-40°C to +85°C)
- Current Handling : Rated for 1.2A saturation current, suitable for moderate power applications
- Self-Resonant Frequency : High SRF (typically >10 MHz) minimizes parasitic effects in target applications
- Robust Construction : Epoxy coating provides mechanical protection and environmental resistance
Limitations:
- Frequency Range : Limited effectiveness above self-resonant frequency
- Size Constraints : Radial through-hole package may not suit space-constrained designs
- Current Saturation : Performance degrades near saturation current limits
- Temperature Coefficient : Inductance variation of approximately 300 ppm/°C
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Current Saturation Issues
- Problem : Inductance drops significantly when approaching saturation current
- Solution : Design with 20-30% margin below specified saturation current (1.2A)
- Implementation : Use current monitoring or implement soft-start circuits
Thermal Management
- Problem : Temperature rise affects inductance and increases DC resistance
- Solution : Ensure adequate airflow and consider thermal derating
- Implementation : Maintain 2-3mm clearance from heat-generating components
Parasitic Effects
- Problem : Stray capacitance and winding resistance impact high-frequency performance
- Solution : Account for parasitic elements in circuit simulation
- Implementation : Use equivalent circuit models including ESR and parallel capacitance
### Compatibility Issues with Other Components
Semiconductor Compatibility
- MOSFETs : Compatible with most switching MOSFETs; ensure dv/dt ratings accommodate inductor flyback voltages
- Diodes : Requires fast recovery diodes in switching applications to prevent reverse recovery issues
- ICs : Compatible with common switching regulator ICs (e.g., LM2596, LT1074)
Capacitor Selection
- Electrolytic Capacitors : Compatible but consider ESR in filter design
- Ceramic Capacitors : Ideal partners for high-frequency decoupling
- Film Capacitors : Recommended for resonant applications
### PCB Layout Recommendations
