Quick Answer
PCB design for EMC compliance requires proper grounding, power supply decoupling, signal routing techniques, and shielding.
Introduction
EMC compliance is mandatory for industrial products. This guide provides practical PCB design guidelines.
Grounding Design
- Use solid ground plane (avoid split ground planes)
- Separate analog and digital grounds, connect at one point
- Star grounding for mixed-signal systems
- Keep ground return paths short
Power Supply Design
- Decoupling capacitors near every IC (0.1μF + 10μF)
- Power plane isolation (separate analog/digital power)
- Filtering for input power (common-mode choke)
- Avoid power plane splits under high-speed signals
Routing Techniques
- Minimize loop area (signal and return path close together)
- Use differential pairs for high-speed signals (USB, Ethernet)
- Avoid right-angle bends (use 45° or curves)
- Route critical signals away from noisy components
Shielding and Filtering
- Use metal enclosure for shielding
- Add EMI filters on I/O cables
- Use ferrite beads on power and signal lines
Real Case Study
InnovChip helped a client pass EMC test (EN 55032 Class B). Problem: Radiated emissions failed. Solution: Optimized PCB layout (shorter traces, better grounding), added shielding can, EMI filters on I/O. Result: Passed with 6dB margin.
FAQ
Q1: What is the minimum clearance for EMC?
3mm minimum clearance for 230V AC circuits. Keep low-voltage signals away from high-voltage.
Q2: How to reduce EMI from switching power supply?
Use shielded inductor, add input EMI filter, minimize switching loop area.
Conclusion
EMC-compliant PCB design requires careful planning. InnovChip offers EMC design review services.
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