Electrostatic Discharge Explained: Causes, Effects, and Prevention Strategies

Feb 23,2021

Electrostatic discharge (ESD) is a phenomenon that causes an electrical surge between two electrically charged objects. This is one of the concerns faced frequently in the printed circuit boards (PCBs). It is also responsible for electrical shortage, PCB breakdown, etc. Certain issues caused due to electrostatic discharge may result in electrical system failure, electrocution, etc. Therefore, it is essential to tackle the problem of electrostatic discharge. However, it is also essential to know what exactly ESD is, what its causes are, and how to resolve the problems. This post introduces the concept of electrostatic discharge followed by its causes and solutions.

Introduction to Electrostatic Discharge (ESD)

The electrostatic discharge (ESD) is the sudden surge of electric charge between two electrically charged elements in proximity. In an electrical or electronic setup like a PCB, as electrostatic induction builds up static electricity increases, which results in sudden ESD. The electrostatic induction takes place when two dissimilarly charged elements come in direct contact or proximity due to the breaking of dielectric between them.

ESD appears as a micro version of lightning. It appears as a spark between the two dissimilarly charged (one negatively and another positively charged) elements, which carries the damaging potential enough to destruct a whole printed circuit board (PCB) or an integrated electrical or electronic circuit.

In a PCB or an electrical or electronic integrated setup, ESD is often caused due to the following reasons.

• Not using an electrostatic wrist strap or protective equipment during troubleshooting electronic equipment may trigger ESD.
• Presence of synthetic materials such as plastic, Styrofoam, etc in close vicinity of electric passage in the electronic circuit.
• The use of forced-air-circulation on the electrically active equipment may cause the accumulation of static electric potential, which eventually results in ESD.

The PCBs may suffer latent or catastrophic damage due to ESD, which might result in partial or complete malfunction/failure of PCBs. Since the damaging potential of ESD is high in the PCBs or electronic integrated setups, it is essential to prevent ESD.

Let us discuss a few preventive measures or solutions to ESD.

Prevention Measures/Solutions for ESD in PCBs

The PCBs can be prevented against ESD by diligently designing the static-free PCBs or by adopting the ESD-preventive PCB fabrication and utilization process. Let us discuss a few guidelines for both the preventive methods.

• ESD Prevention Guidelines for PCB Design:

  The following tips will help prevent ESD buildup in PCB design.

  • In order to reduce parasitic inductance, it is important to reduce electric line length. Higher parasitic inductance prevents the protection circuits from appropriate function, therefore causes ESD. Reducing line length and parasitic inductance eventually results in the prevention of ESD.

  • Adequate spacing/air gap between two consecutive electronic components must be provided. This air gap spacing prevents direct voltage interaction between two components. In case of high voltage operation of the PCB, appropriate insulation between two components may be required.

  • PCB’s edges are highly susceptible to ESD buildup, therefore IC tracks must not run nearby PCB edges.

  • The use of isolation pads for the metallic connectors can be helpful in preventing ESD in the PCBs.

• ESD Prevention Guidelines by Process:

  The following steps can be followed to prevent ESD during PCB fabrication and utilization.

  • During PCB fabrication, it is essential to form a static-free or ESD-preventive environment. This can involve the ESD-protection of fabrication tables. The work-tables must be protected with ESD-free mats and proper earthing. According to NFPA-77, the practices to create an ESD-preventive environment include the use of anti-static grounding mats, high-resistance wrist bands, etc.

  • The use of static-resistant packaging material and paints can resist ESD occurrence.

Now that the concept of electrostatic discharge (ESD) in PCBs is persuaded, it is essential to work with a PCB contract manufacturer in the USA that offers ESD-preventive design and fabrication services such as Creative Hi-Tech. The company offers high quality and secured designs of PCBs along with rapid-fabrication services. The company is ISO 9001:2015, IPC-WHMA-A-610, and IPC-CC-830B certified. Also, they offer IPC-A-610-D and ANSI/J-STD-001 compliant PCB assembly services to ensure optimum quality and performance.

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