Common Mode Choke Coil Film Type DLP11S/DLP11T Series (0504 Size) # Technical Documentation: DLP11SN670SL2L EMI Suppression Filter
Manufacturer : MURATA
Component Type : EMI Suppression Ferrite Chip Bead
## 1. Application Scenarios
### Typical Use Cases
The DLP11SN670SL2L is specifically designed for high-frequency noise suppression in electronic circuits, primarily targeting electromagnetic interference (EMI) and radio frequency interference (RFI) mitigation. Typical applications include:
- Power Supply Lines : Installed on DC power rails to suppress switching noise from DC-DC converters and voltage regulators
- Signal Lines : Applied to high-speed digital interfaces (USB, HDMI, Ethernet) to reduce electromagnetic emissions
- RF Circuits : Used in wireless communication modules to prevent harmonic radiation and improve signal integrity
- Clock Circuits : Suppresses high-frequency noise from crystal oscillators and clock distribution networks
### Industry Applications
- Consumer Electronics : Smartphones, tablets, laptops, and gaming consoles for EMI compliance
- Automotive Electronics : Infotainment systems, ADAS modules, and engine control units meeting CISPR 25 requirements
- Industrial Control Systems : PLCs, motor drives, and sensor interfaces in harsh electromagnetic environments
- Medical Devices : Patient monitoring equipment and diagnostic instruments requiring high reliability
- Telecommunications : Base station equipment, network switches, and routing hardware
### Practical Advantages and Limitations
Advantages:
- High Impedance at Target Frequencies : Provides 67Ω typical impedance at 100MHz, effectively attenuating noise in the critical 30-1000MHz range
- Compact Size : 0402 package (1.0×0.5mm) enables high-density PCB layouts
- Low DC Resistance : 0.15Ω maximum ensures minimal voltage drop in power applications
- Temperature Stability : Maintains performance across -55°C to +125°C operating range
- RoHS Compliance : Meets environmental regulations for lead-free manufacturing
Limitations:
- Frequency-Specific Performance : Effectiveness decreases outside the designed frequency range (primarily 10-1000MHz)
- Current Handling : Maximum rated current of 500mA may be insufficient for high-power applications
- Saturation Effects : DC bias current can reduce impedance performance at higher current levels
- Board Space Constraints : Small package requires precise manufacturing processes
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Pitfall 1: Incorrect Placement
- Issue : Placing ferrite beads too far from noise sources or sensitive components
- Solution : Position beads as close as possible to noise-generating ICs or connector interfaces
Pitfall 2: Overlooking DC Bias Effects
- Issue : Not accounting for impedance reduction under operating current conditions
- Solution : Select beads based on actual operating current, not just zero-bias specifications
Pitfall 3: Resonance Issues
- Issue : Parasitic capacitance creating resonant circuits that amplify specific frequencies
- Solution : Use simulation tools to model bead behavior and avoid resonant frequencies in operating bands
### Compatibility Issues with Other Components
Power Management ICs:
- Ensure the bead's DC resistance doesn't cause excessive voltage drop for LDOs or switching regulators
- Verify current rating exceeds maximum load current with adequate margin
High-Speed Digital ICs:
- Check that bead impedance doesn't degrade signal integrity for fast edge rates
- Consider using multiple beads in parallel for high-current digital circuits
RF Components:
- Avoid using beads on RF signal paths where they may introduce unwanted phase noise
- Use alternative filtering methods for sensitive RF receiver chains
### PCB Layout Recommendations
Placement Strategy:
- Position beads immediately after connectors to prevent noise ingress/egress
- Place close to switching regulator outputs and clock generator outputs
- Use
