Electrostatic Discharge (ESD) Protection Design Guide

Key Takeaways

• Electrostatic Discharge (ESD) is the momentary flow of electric current between two electrically charged objects.

• ESD failures can be segmented into soft failures, latent defects, and catastrophic failures.

• The ESD protection circuit diverts the ESD current flow by offering a low-impedance path.

ESD failures can be segmented into soft failures, latent defects, and catastrophic failures

Electrostatic discharge is a serious concern in any electronic circuit. Using an electrostatic discharge wrist strap, work mat, and workbench are basic anti-electrostatic discharge methods in electronic hardware development set-ups. However, following electrostatic discharge (ESD) protection design guidelines while transferring the circuit diagram to a PCB is important for protection against ESD. 

First of All, What Is Electrostatic Discharge?

ESD can be classified as:

Device-level ESD is more detrimental than system-level ESD. It is essential to protect electronic components from ESD, irrespective of whether they are mounted to a PCB or unmounted.

Many materials possess the property to conduct and accumulate electric charges. The electric charge stored in the material can be due to electrostatic induction or triboelectric charging. Whenever the object with stored charges comes into the vicinity of another electrically charged object, current flow between them due to the potential differences occurs. This flow continues until the charge balance is restored.

Degrees of ESD Failure

ESD-generated voltages and currents have fast rise times and high peak voltages. These currents and voltages are more than enough to completely blow off semiconductors and sensitive components. In fact, the degree of ESD failure ranges from subtle to harsh. ESD failures can be categorized as soft failures, latent defects, or catastrophic failures.