How to Address Power Supply Noise in High-Frequency PCB Boards

Power supply noise is a critical type of interference in high-frequency PCB boards that needs to be effectively managed. By analyzing the features and root causes of power supply noise, practical solutions can be implemented to minimize its impact.

Types of Power Supply Noise Interference:

• Distributed Noise: Caused by the inherent impedance of the power supply, impacting high-frequency signals. Requires a low-noise power supply and clean ground/power.
• Common Mode Field Interference: Interference between power supply and ground due to common-mode voltage.
• Differential Mode Field Interference: Interference between power supply and input/output power lines.
• Power Line Coupling: Transmission of interference from power lines to other devices.

Countermeasures to Eliminate Power Supply Noise:

• Optimize Through Holes: Ensure proper openings in the power layer for vias to pass through without affecting signal loops.
• Ground Wire Placement: Each signal should have a dedicated signal loop with minimal loop area.
• Power Supply Noise Filter: Install filters to suppress internal noise and improve system safety and anti-interference capabilities.

By implementing these solutions, the interference of power supply noise can be effectively suppressed, ensuring the smooth operation of high-frequency PCB boards.

Strategies to Reduce Power Supply Noise in PCB Design

• Power isolation transformer: Separate power loops to effectively isolate common-mode loop currents.
• Power regulator: Clean power supply reduces noise levels significantly.
• Optimal wiring: Avoid placing power lines on the edge of the board to prevent interference.
• Separate analog and digital power supplies: Sensitive high-frequency devices require separate supplies to reduce digital noise.
• Avoid overlapping power supplies on different layers: Staggering power supplies reduces noise coupling.
• Isolate sensitive components: Keep components like PLLs away from noisy power supplies.
• Strategic power cord placement: Reduce signal loops by positioning power lines next to signal lines.
• Utilize bypass capacitors: Connect capacitors to ground to bypass noise interference.

Power supply noise can disrupt circuits and should be minimized to ensure optimal performance. By implementing these strategies, you can effectively reduce power supply noise and enhance the overall functionality of your PCB design.