In PCB design, effective ESD (Electrostatic Discharge) protection can be achieved through strategic layering, layout, and installation adjustments. ESD protection aims to shield delicate semiconductor chips from static electricity originating from humans, the environment, or even other electronic components, which can damage insulation layers, MOSFET and CMOS gates, PN junctions, and wiring. Here are some recommended techniques to enhance ESD protection in PCB designs.

Key ESD Protection Strategies for PCB Design

1. Use Multi-Layer PCBs:
   • Multi-layer PCBs with dedicated ground and power planes can significantly reduce common-mode impedance and inductive coupling, lowering ESD susceptibility compared to double-sided PCBs.
   • Position each signal layer near a power or ground plane.
   • In high-density PCBs, consider using internal layers for more robust protection.
2. Grid Layout for Double-Sided PCBs:
   • Create a tightly woven power and ground grid, placing power lines near ground lines and interconnecting vertical and horizontal lines as much as possible.
   • Maintain a grid spacing of no more than 60mm, ideally less than 13mm for optimal ESD performance.
3. Compact Circuit Design:
   • Compact circuits reduce trace length and minimize potential paths for ESD interference, enhancing overall robustness.
4. Connector Placement:
   • Place connectors on one side of the PCB to minimize exposure to ESD.

1. Power Line Positioning:
   • Route power lines from the center of the board, avoiding areas likely to be exposed to direct ESD.
2. Ground Layer Design for Connectors:
   • On PCB layers below connectors exposed to ESD, add wide chassis ground or polygon fills and connect them with vias approximately every 13mm.
3. Mounting Hole Grounding:
   • Add mounting holes along the PCB edges connected to the chassis ground with solder-mask-free pads.
   • Use screws with embedded washers to ensure tight contact with the metal chassis or ground plane.
4. Stand-Off Zones Between Chassis and Circuit Grounds:
   • Create a consistent “standoff zone” of 0.64mm between chassis and circuit ground on each layer.
5. Chassis and Circuit Ground Connections:
   • Connect the chassis ground and circuit ground with a 1.27mm-wide line every 100mm near the mounting holes, and place mounting pads or holes between these grounds.
   • Use beads or high-frequency capacitors to jumper connections if necessary.
6. Exposed Chassis Grounds:
   • If a metal shield or chassis isn’t used, omit solder mask on the top and bottom chassis grounds so they can act as discharge electrodes.
7. Ring Grounding:
   • Create a ring ground path around the board, except near connectors and chassis ground.
   • Ensure a width of at least 2.5mm on all layers, with vias spaced every 13mm.
   • Connect the ring ground to a common ground across layers.
   • For boards in metal chassis, connect the ring ground to the common ground; for unshielded boards, connect to the chassis ground. Avoid solder resist on the ring ground and leave a 0.5mm gap to prevent large loops. Maintain a minimum 0.5mm distance between signal wires and ring ground.

These design practices are critical for optimizing PCB performance and enhancing resistance to ESD in sensitive applications.

KKPCB conducts research on special processing technologies such as ordinary double-sided boards, thick copper circuit boards, high-frequency circuit boards, HDI circuit boards, rigid-flexible circuit boards, FPC flexible boards, buried blind hole circuit boards, and IC carrier boards. Provides PCB design, PCB layout, PCB prototyping and PCB assembly services.