As electronic devices become more complex and faster, achieving electrostatic discharge (ESD) immunity is increasingly challenging. One effective approach to studying ESD in R&D is simulation.
Electrostatic Discharge (ESD) is a phenomenon where static electricity discharge happens between two electrically charged objects when they are close, such as the human finger approaching an electronic device. The high current pulse generated by the discharge process can flow into the electronic device, causing damage to internal PCBs and IC devices. With the trend in the electronics industry to increase operating speeds and decrease operating voltages of electronic components, devices are even more susceptible to ESD, and designing-in protection to avoid damage, upset, or failure is essential.
CST Studio Suite software offers true transient simulation, incorporating non-linear elements and field visualization for contact ESD. A primary method for testing ESD involves using an ESD generator, with a 3D model developed using CST Studio Suite. This model is detailed in an excellent white paper by Dassault Systèmes.
Integrating simulations early in product development significantly eases the process of achieving ESD compliance, mitigating risks before they arise in later stages.
How to Mitigate ESD Failure Risks?
Identify Critical and Vulnerable Areas
The environment around the PCB and sensitive circuitry is extremely important for estimating possible ESD events: floating metal parts or pin connectors might cause ESD events and spark creation.
Not all circuits or pins are equally sensitive to high voltage or surge currents. Understanding the requirements and performing ESD simulations can provide valuable insights into how your layout behaves, showing how electromagnetic fields propagate and spread across it.
Effective Strategies to Control ESD Spread
Component Selection: Proper placement of TVS diodes can be highly beneficial, but incorrect choices can be detrimental. Selecting diodes based on characteristics like breakdown and clamping voltage, and dynamic resistance, requires an understanding of operational conditions of the product. Simulations can reveal how the electromagnetic wave spreads and dissipates depending on the chosen TVS diode. Think of it like having well-placed drains to prevent your house from flooding.
Layout Design and Modifications: Engineers know that current flows through paths of least resistance towards the ground. In complex layouts with numerous components and limited grounding, especially where ground is not at 0V, this becomes more intricate. Simulations, even without full active component models, help understand how the layout affects field distribution and guide modifications for better ESD outcomes. In addition, ensure PCB layout design adheres to creepage and clearance standards and verify compliance during DFM checks.
Conclusion
Incorporating ESD simulations early in the product development process is crucial for ensuring the reliability and safety of modern electronic devices. By identifying vulnerable areas and implementing effective strategies such as proper component selection and layout design/ modifications, engineers can significantly mitigate ESD risks. Embracing these practices not only enhances product performance but also accelerates the path to compliance, ultimately leading to more robust and resilient electronic systems.
Compare the difference the diode makes, as demonstrated by the simulation:
Wish to know more about ESD simulation?
- Get to know the software and contact us about CST Studio Suite
- Experimenting with EM simulations for the first time? Try our Simulation Starter
- Get in touch with our ESD expert Vesna Somero
