In the design of PCB board, anti-ESD design of PCB can be realized through layering, proper layout and installation. During the design process, most design changes can be limited to adding or removing components through prediction. By adjusting PCB layout and wiring, ESD can be well prevented.

Static PCB electricity from the human body, the environment and even inside the electric PCB board copying equipment will cause various damage to the precision semiconductor chip, such as penetrating the thin insulation layer inside the components; Damage to the gates of MOSFET and CMOS components; CMOS trigger lock in PCB copy; Short-circuit reverse bias PN junction; Short-circuit positive PCB copy board biased PN junction; PCB board melting welding wire or aluminum wire in PCB board board part of active device. In order to eliminate the interference and damage of electrostatic discharge (ESD) to electronic equipment, it is necessary to take a variety of technical measures to prevent.

In the design of PCB board, anti-ESD design of PCB can be realized through layering and proper layout of PCB copy board and PCB copy board wiring and installation. During the design process, most design changes can be limited to adding or removing components through prediction. By adjusting PCB layout and wiring, it can prevent PCB ESD. Here are some common precautions.

Use multilayer PCBS whenever possible. The ground and power planes, as well as the tightly spaced signal line-ground lines, can reduce common-mode impedance and inductive coupling to 1/10 to 1/100 of a double-sided PCB compared to a double-sided PCB. Try to place each signal layer close to a power or ground layer. For high-density PCBS with components on both the top and bottom surfaces, very short connections, and lots of ground filling, consider using inner lines. For double-sided PCBS, tightly interwoven power supplies and grids are used. The power cord is next to the ground and should be connected as much as possible between the vertical and horizontal lines or fill zones. The size of one side grid PCB shall be less than or equal to 60mm, if possible, grid size shall be less than 13mm.

How to design anti-ESD of PCB board

Ensure that each circuit PCB copy board is as compact as possible.

Put all connectors aside as much as possible.

If possible, direct the power PCB lines from the center of the card away from areas that are directly exposed to ESD.

On all PCB layers below the connectors leading out of the chassis (PCB copy boards are vulnerable to ESD), place wide chassis or polygon filled floors and connect them together with holes at approximately 13mm intervals.

PCB copy board mounting holes are placed on the edge of the card, and the top and bottom pads of PCB copy board open flux are connected to the ground of the chassis around the mounting holes.

When assembling PCB, do not apply any solder on PCB copy pad of top or bottom layer. Use screws with built-in PCB copy washers to achieve tight contact between PCB and PCB copy/shield of metal chassis or support on ground surface.

The same “isolation zone” should be set up between the chassis floor and the circuit floor on each layer; If possible, keep the spacing at 0.64mm.

At the top and bottom of the card near the PCB mounting hole, connect the chassis ground and the circuit ground together with 1.27mm wide wire every 100mm along the chassis ground wire. Adjacent to these connection points, a pad or mounting hole for installation is placed between the chassis floor and the circuit floor PCB board. These ground connections can be cut with a blade to remain open, or jump with magnetic beads/high frequency capacitors.

If the circuit board will not be placed in the metal box or PCB copy shielding device, the top and bottom chassis ground wire of the circuit board can not be coated with solder resistance, so that they can be used as ESD arc discharge electrode.

To set up a ring around the circuit in the following PCB copying mode:

(1) In addition to the edge of the PCB board reader and the chassis, the entire periphery is placed around the ring path.

(2) Ensure that the width of all layers is greater than 2.5mm.

(3) The holes are connected in a ring every 13mm.

(4) Connect the annular ground with the common ground of multi-layer PCB copy circuit together.

(5) For double-sided PCB boards installed in metal cases or shielding devices, the ring ground should be connected to the circuit in common. For unshielded double-sided circuits, the ring ground should be connected to the chassis, the ring ground should not be coated with flux, so that the ring ground can act as an ESD discharge rod, at least a 0.5mm wide gap should be placed somewhere on the ring ground (all layers), so that the PCB board can not form a large loop. Signal wiring should not be less than 0.5mm away from the ring ground.