Here are some common preventive measures. Whenever possible, use multi-layer PCBs, along with ground planes and power planes. Tightly spaced signal lines and ground planes can reduce common-mode impedance and the coupling effect between signal layers, improving the performance of double-sided PCBs by a factor of 1/10 to 1/100 compared to traditional designs. Ensure that each signal layer is placed as close as possible to either a power or ground layer.
For high-density PCBs with components mounted on both the top and bottom surfaces, and where connectors are very short with many fill positions, consider incorporating internal layers for routing. For dual-layer PCBs, use tightly interwoven power and ground nets. Keep the power lines close to the ground lines, and aim to connect them at both vertical and horizontal intersections, or through the filled areas, to improve the grounding effectiveness.
By optimizing PCB layout and routing, ESD (electrostatic discharge) protection can be significantly enhanced. Static electricity from human contact, environmental factors, or even electronic equipment can cause severe damage to complex semiconductor chips. Such damage can include puncturing the thin insulating layer inside components, destroying the gates of MOSFET and CMOS devices, triggering faults in locked CMOS circuits, shorting a PN junction, or even causing a short circuit in a forward-biased PN junction. In some cases, ESD can lead to the melting of solder joints or aluminum wires inside active devices.
1. To mitigate electrostatic discharge (ESD) interference and prevent damage to electronic equipment, it is essential to implement various technical measures for protection. In PCB design, ESD protection can be achieved through proper layering, layout, and installation techniques. During the design phase, most design adjustments can be limited to adding or removing components based on predictions. By optimizing the PCB layout and routing, effective ESD protection can be realized.
2. If possible, the grating size should be no larger than 60mm, with an ideal size of less than 13mm.
3. Ensure that each circuit is as compact as possible.
4. Position connectors away from sensitive areas as much as possible.
5. If feasible, route the power cord to enter the card from the center and avoid placing it near areas prone to ESD.
6. On all PCB layers beneath connectors exposed to the exterior (which are more vulnerable to ESD), place a wide chassis or polygonal fill, connecting them at approximately 13mm intervals.
7. Position the mounting holes along the edge of the board and connect them to the chassis’ bottom panel, ensuring that no solder is applied to the top or bottom pads during assembly.
8. Use screws with embedded washers to achieve a tight connection between the PCB and the metal chassis/shield, or to the ground plane.
9. Maintain consistent “isolation” between the chassis and the circuit on each layer, with a recommended separation distance of 0.64mm. At the top and bottom of the card, near the mounting holes, connect the chassis and circuit with 1.27mm wide traces every 100mm along the chassis ground. Place mounting holes or pads near these points to facilitate the connection between the chassis and the circuit.
10. These ground connections can traverse the traces to keep pathways clear, or alternatively, use beads or high-frequency capacitors to create the necessary bypass.
11. If the circuit board is not enclosed within a metal chassis or shield, do not coat the top or bottom layers of the PCB or the bottom panel, as these surfaces should serve as discharge electrodes for ESD arcs.
12. Implement a ring ground around the circuit as follows:
(1) Place a circular trace around the entire perimeter, excluding the edge connector and chassis areas.
(2) Ensure the ring width on all layers is greater than 2.5mm.
(3) Connect the holes in a circular pattern every 13mm.
(4) Link the ring ground to the common ground of the multilayer circuit.
(5) For double-sided PCBs installed in a metal chassis or shield, the ring ground should be connected to the circuit’s common ground. For unshielded double-sided circuits, the ring ground should connect to the chassis, but the ring plane should remain uncoated to function as an ESD discharge path. Ensure at least one 0.5mm wide gap is placed in a specific position of the ring to prevent the formation of large loops. The signal trace distance from the ring ground should not be less than 0.5mm.
If your have any questions about PCB ,please contact me info@wellcircuits.com
For high-density PCBs with components mounted on both the top and bottom surfaces, and where connectors are very short with many fill positions, consider incorporating internal layers for routing. For dual-layer PCBs, use tightly interwoven power and ground nets. Keep the power lines close to the ground lines, and aim to connect them at both vertical and horizontal intersections, or through the filled areas, to improve the grounding effectiveness.
By optimizing PCB layout and routing, ESD (electrostatic discharge) protection can be significantly enhanced. Static electricity from human contact, environmental factors, or even electronic equipment can cause severe damage to complex semiconductor chips. Such damage can include puncturing the thin insulating layer inside components, destroying the gates of MOSFET and CMOS devices, triggering faults in locked CMOS circuits, shorting a PN junction, or even causing a short circuit in a forward-biased PN junction. In some cases, ESD can lead to the melting of solder joints or aluminum wires inside active devices.
1. To mitigate electrostatic discharge (ESD) interference and prevent damage to electronic equipment, it is essential to implement various technical measures for protection. In PCB design, ESD protection can be achieved through proper layering, layout, and installation techniques. During the design phase, most design adjustments can be limited to adding or removing components based on predictions. By optimizing the PCB layout and routing, effective ESD protection can be realized.
2. If possible, the grating size should be no larger than 60mm, with an ideal size of less than 13mm.
3. Ensure that each circuit is as compact as possible.
4. Position connectors away from sensitive areas as much as possible.
5. If feasible, route the power cord to enter the card from the center and avoid placing it near areas prone to ESD.
6. On all PCB layers beneath connectors exposed to the exterior (which are more vulnerable to ESD), place a wide chassis or polygonal fill, connecting them at approximately 13mm intervals.
7. Position the mounting holes along the edge of the board and connect them to the chassis’ bottom panel, ensuring that no solder is applied to the top or bottom pads during assembly.
8. Use screws with embedded washers to achieve a tight connection between the PCB and the metal chassis/shield, or to the ground plane.
9. Maintain consistent “isolation” between the chassis and the circuit on each layer, with a recommended separation distance of 0.64mm. At the top and bottom of the card, near the mounting holes, connect the chassis and circuit with 1.27mm wide traces every 100mm along the chassis ground. Place mounting holes or pads near these points to facilitate the connection between the chassis and the circuit.
10. These ground connections can traverse the traces to keep pathways clear, or alternatively, use beads or high-frequency capacitors to create the necessary bypass.
11. If the circuit board is not enclosed within a metal chassis or shield, do not coat the top or bottom layers of the PCB or the bottom panel, as these surfaces should serve as discharge electrodes for ESD arcs.
12. Implement a ring ground around the circuit as follows:
(1) Place a circular trace around the entire perimeter, excluding the edge connector and chassis areas.
(2) Ensure the ring width on all layers is greater than 2.5mm.
(3) Connect the holes in a circular pattern every 13mm.
(4) Link the ring ground to the common ground of the multilayer circuit.
(5) For double-sided PCBs installed in a metal chassis or shield, the ring ground should be connected to the circuit’s common ground. For unshielded double-sided circuits, the ring ground should connect to the chassis, but the ring plane should remain uncoated to function as an ESD discharge path. Ensure at least one 0.5mm wide gap is placed in a specific position of the ring to prevent the formation of large loops. The signal trace distance from the ring ground should not be less than 0.5mm.
If your have any questions about PCB ,please contact me info@wellcircuits.com
