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In the design of printed circuit boards (PCBs), effective anti-ESD measures can be achieved through strategic layering, proper layout, and installation. Adjusting the PCB layout effectively prevents ESD incidents. Utilizing multi-layer PCBs whenever possible is recommended. Compared to double-sided PCBs, multi-layer boards offer ground and power planes, and closely spaced signal lines and ground lines, which reduce common-mode impedance and inductive coupling. This enables significant improvements, typically ranging from 1/10 to 1/100 of the impedance seen in double-sided PCBs. Components are mounted on both the top and bottom surfaces with very short connection lines.

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This version clarifies the points and improves readability while maintaining the original meaning.

Static electricity from human bodies, the environment, and even within electronic equipment can cause various damages to precision semiconductor chips. This includes penetration of thin insulating layers inside components, short-circuiting reverse-biased PN junctions, short-circuiting forward-biased PN junctions, and melting bonding wires or aluminum wires inside active devices. To prevent interference and damage caused by electrostatic discharge (ESD) to electronic equipment, several technical measures must be implemented.

In PCB board design, anti-ESD measures can be achieved through layering, proper layout, and installation techniques. During the design process, most modifications can focus on predicting component additions or removals. Adjusting the PCB layout effectively prevents ESD. Below are common precautions:

1. **Use of Multi-layer PCBs:** Prefer multi-layer PCBs over double-sided ones. Ground and power planes, along with closely spaced signal lines and ground lines, reduce common-mode impedance and inductive coupling, thereby mitigating ESD.

2. **Optimal Signal Layer Placement:** Place each signal layer as close as possible to a power layer or ground layer. For high-density PCBs with components on both surfaces, consider utilizing inner layers for very short interconnects and extensive ground fills.

3. **Power and Ground Grids:** For double-sided PCBs, use densely woven power and ground grids. Ensure close proximity between power and ground lines, maximizing vertical and horizontal wire connections or padding, with a grid size ideally ≤ 60mm and preferably < 13mm.
4. **Compact Circuit Design:** Design circuits as compactly as possible, minimizing exposed connectors. Prefer routing power cables through the card center to avoid direct ESD exposure areas.

5. **Chassis Grounding:** Place wide chassis grounds or polygon fills on all PCB layers beneath connectors prone to direct ESD hits. Connect these grounds through vias spaced approximately 13mm apart, with mounting holes at the card edge featuring solder-free top and bottom pads connected to chassis ground.

6. **Isolation and Ground Connections:** Maintain isolation areas of 0.64mm between chassis ground and each layer’s circuit ground. Connect these grounds via 1.27mm-wide wires every 100mm along the chassis ground, using pads or mounting holes adjacent to these connection points.

7. **Ring Ground Design:** Implement a ring ground around the circuit, wider than 2.5mm on all layers, connected annularly via via holes every 13mm. Connect the ring ground to the multilayer circuit’s common ground, ensuring it connects to chassis ground for unshielded double-sided circuits.

8. **ESD Protection Components:** Place series resistors and magnetic beads on susceptible circuits, particularly near connectors and at both ends of long signal lines. Use transient protectors and filter capacitors within 25mm of receiving circuits to mitigate ESD effects effectively.

9. **Optimized Routing:** Ensure signal lines are kept short and direct, and avoid parallel routing of protected and unprotected signal lines. High-frequency filtering and careful placement away from board edges and I/O circuits are essential.

10. **Installation Considerations:** Insert PCBs into chassis rather than openings or internal seams, avoiding signal line interference under beads and between pads.

By adhering to these guidelines, PCB designs can effectively minimize the risks associated with ESD, ensuring the reliability and longevity of electronic equipment.