Points for Selecting ESD Suppression Circuits and Components for Automotive Electronic Devices

1-1. When Only ESD Suppression is Required: MLCV Alone

When ESD suppression is a top priority, the use of an MLCV alone is effective. MLCVs have high ESD immunity and can effectively protect ICs and electronic circuits without the discharges between terminals that MLCCs cause. In addition, as they do not require capacitors like MLCCs do, they provide excellent performance even in environments that require miniaturization and high immunity. The use of an MLCV alone also provides the benefit of reducing the number of components and enabling simple circuit configurations in designs with the purpose of ESD suppression.

1-2. To Achieve Noise Suppression As Well: Parallel configuration of MLCC + MLCV

When noise suppression is required in addition to ESD suppression, a configuration in which MLCC and MLCV are connected in parallel is suitable. MLCCs have a large electrostatic capacitance and play a role in reducing noise. However, when high-voltage ESD is applied, there is a risk of discharge between terminals and deterioration of electrical characteristics. Combined use with an MLCV can protect the MLCC from the impact of ESD and help maintain stable performance.

This parallel configuration is particularly suitable for automotive communications and the protection of high-precision electronic devices as it provides a good balance between noise suppression and ESD suppression. Adjusting the capacitance of the MLCC according to the design enables finer noise suppression control. As a result, ESD suppression can be enhanced while improving communication quality. Fig. 1 shows circuit configurations for each use case.

2-1. Reduction of IC Failure Risk and Avoidance of NTF

Use of an ESD suppression component can protect critical ICs, especially those that control automotive communications and drive systems, while significantly reducing the risk of electrostatic discharge failures. As a result, the reliability of the entire system is improved, and failures that occur in critical components such as transceiver ICs as well as NTFs (No Trouble Found, non-reproducible failures) can be prevented.

2-2. Importance of Judgment from the Supply Side (BCP) and Comprehensive Perspectives

When choosing ESD suppression components, simply choosing those with high performance is not enough. You also need to consider the stability of the supply such as the manufacturer's supply system, component compatibility, and future business continuity plans (BCPs). In addition, it is important to consider the most suitable ESD suppression components from comprehensive perspectives, including comparisons with components such as Zener diodes (ZDs) and ESD suppressors.

4-1. New Evaluation Method and Discharge Mechanism Analysis

Through observation of discharges and repeated application tests using the ESD visualization camera introduced in the previous article, the cause of defects that were previously often overlooked can be clarified. In order to improve the reliability of products, especially in the automotive field, there is a need to enhance discharge mechanism analysis and verification methods.

4-2. ESD Suppression to Respond to Higher-speed, Higher-reliability Automotive Communications

In addition, with the evolution of automotive communication technology, which enables higher speed communication lines that support 5G and autonomous driving technology, there is growing demand for ESD suppression components with higher immunity and lower capacitance. The development of next-generation components such as MLCVs and their effective evaluation will be the key to improving the performance and safety of automotive electronic devices in the future.