PCBA Design for Portable Medical Devices

PCB EMC Design Specifications and Anti-interference Measures: 1. Grounding Design: - Single-point Grounding: Low-frequency circuits, reduce ground loops - Multi-point Grounding: High-frequency circuits, reduce grounding impedance - Mixed Grounding: Different frequencies handled separately - Complete Ground Plane: Multi-layer board design with complete ground layer 2. Power Filtering: - Decoupling Capacitor: Place near each IC power pin - Filter Capacitor: Large capacity electrolytic capacitor at power inlet - Ferrite Bead Isolation: Separate analog and digital power supplies - Power Plane: Multi-layer board complete power layer 3. Signal Integrity: - Impedance Control: Trace impedance matching reduces reflections - Differential Routing: High-speed differential signals equal length and parallel - Return Path: Ensure signals have complete return path - Crosstalk Control: Signal line spacing meets requirements 4. Shielding Design: - Metal Enclosure: Equipment-level shielding reduces radiation - Shielding Can: Local shielding for key circuits - Filter Connector: Filtering at interface to suppress conduction - Grounding Spring: Ensure good grounding of shielding 5. Anti-interference Measures: - TVS Diode: Surge protection at interface - Common Mode Inductor: Suppress common mode interference - Optocoupler Isolation: Digital-analog isolation - Software Filtering: Digital filtering reduces false triggers 6. Design Checklist: - Is ground plane complete - Are decoupling capacitors placed nearby - Do high-speed signals have complete return path - Is there surge protection at interface - Is there filtering at power inlet

← Makalelere Dön