In modern electronic devices, multilayered ceramic capacitors (MLCC) have become one of the most widely used components on printed circuit boards (PCB) due to their advantages of small size, large capacity, and low cost. However, the brittle nature of their ceramic dielectric material leads to a fatal weakness - crack failures caused by mechanical stress. During PCB manufacturing or final assembly, substrate bending is almost inevitable, especially in automated welding (such as reflow soldering) or mechanical assembly stages, where the stress on the ceramic body exceeds the critical point, resulting in microcracks. As electronic devices become increasingly thin and lightweight, the reduction in substrate thickness further amplifies the risk of bending. MLCC are prone to cracks caused by substrate bending, leading to short circuits and other faults. This problem is particularly prominent in large-sized MLCC and needs to be addressed urgently. To this end, EYANG has developed open-circuit capacitors to cope with this issue.

The distance between the internal electrodes and the end electrodes in ordinary capacitors is short (Figure 1). When the substrate bends and cracks occur, these cracks may penetrate the internal electrode layer (Figure 2), causing short circuits between the electrodes. In more serious cases, it may even lead to system-level failures or even fire risks.

Figure 1: Internal Structure of Ordinary Capacitor

Figure 2: Internal structure of a common capacitor when cracks occur due to substrate bending

The bypass capacitor adopts a redundant isolation structure, with a certain safety distance between the internal electrodes and the end electrodes (Figure 3). When the substrate bends and cracks occur, the cracks appear in the isolation area of the electrodes (Figure 4), causing the capacitor to open circuit rather than short circuit, thereby cutting off the path for fault propagation.

Figure 3: Internal Structure of Open-Circuit Capacitor

Figure 4: Internal structure of the open-circuit capacitor when cracks occur after the substrate is bent

The bypass capacitor, due to its anti-failure characteristics, has gradually been applied in multiple critical fields.

1. Consumer electronics and mobile devices

Open-circuit capacitors are applied to the edge areas of the mainboards of smartphones and tablets (which are prone to compression) as well as the connection points of flexible PCB (FPC). For example, in scenarios where the camera module wiring of a mobile phone is repeatedly bent, the open-circuit design can prevent the lens function from being paralyzed due to capacitor short circuits.

2. Automotive Electronic System

In the engine control unit (ECU), electric power steering (EPS) and brake control module, open-circuit capacitors are able to withstand the high-temperature and vibration environment of the engine compartment, ensuring that safety-critical systems (such as airbag controllers) remain in a "fail-safe" state under mechanical impacts.

3. Industrial automation equipment

Programmable logic controllers (PLC), servo drives, etc. need to withstand long-term mechanical vibrations and have extremely high maintenance costs. Open-circuit capacitors are applied in the power input filtering and I/O signal conditioning circuits of these devices to ensure stable operation and reduce the rate of unexpected downtime on the production line.

The bypass capacitor represents a paradigm shift for electronic components from "passive bearing" to "active defense". With the increasing reliability requirements for equipment in AI, electric vehicles, and Industry 4.0, the "fail-safe" design concept will become a standard feature for high-performance systems. EYANG bypass capacitors, through their advanced design and performance, provide higher stability and reliability for electronic devices. In the future, as electronic products continue to develop and demand increases, EYANG bypass capacitors will continue to play an important role, promoting the development and innovation of electronic devices.