Flex Crack Countermeasures in MLCCs Vol.2

TDK offers a wide range of solutions for various products and applications.

*Please refer to Vol.1 for Soft Termination, Low Resistance Soft Termination, and fail-safe (Safety Design) products.

MEGACAP are products featuring metal frames attached to the terminal electrodes of MLCC. 
Because the metal frames absorb stress caused by thermal shock and board deflection, these capacitors provide exceptional resistance against them. 
Furthermore, the stacked (two-chip) type achieves twice the capacitance with the same mounting area, making it effective for saving board space.

No cracks occurred even with 10 mm of board bending

Below are the results of the board deflection test.
In a comparison where the board was bent by 10 mm, body cracks were observed in standard terminal products, whereas no cracks were found in MEGACAP products.

Features of MEGACAP (with Metal Frames)

• Superior resistance to mechanical stress and thermal shock due to the metal frame structure
• Doubles capacitance within the same footprint thanks to the stacked (two-chip) structure
• C0G lineup available, offering stable temperature and DC bias characteristics
• Mountable on aluminum substrates (aluminum PCBs)

While MEGACAP can relieve mechanical stress thanks to its metal frames, it also has the drawback of increasing resistive components such as ESR. To overcome this drawback, we completely redesigned the product structure and commercialized a new type of MEGACAP that minimizes resistance. Its key feature is a structure in which MLCCs are arranged side by side.

Horizontal multi-chip structure suppresses product height, ESR, and ESL

While conventional series stack MLCCs vertically, the CA series adopts a structure that places MLCCs horizontally (side by side). Even when more MLCCs are added, the product height and center of gravity barely increase, making it easier to reduce the vibration stress placed on the components. In addition, because each MLCC can be placed close to the board, increases in ESR and ESL are suppressed even when adding MLCCs. Thanks to this structure, the CA series is available in configurations up to a 3-chip structure, meeting the demand for higher capacitance. Furthermore, low resistance is achieved by optimizing the metal terminal material.

➡Current　●Center of gravity

Impedance / ESR Reduction

The graph below shows a comparison of the frequency characteristics of impedance and ESR.The new CA series (blue) has lower ESR than the conventional CKG series (black). Comparing them at the resonant frequency (SRF), the ESR of the new series is reduced by approximately 60% compared to the conventional series. 
Accordingly, a similar reduction in heat generation is expected (heat generation is proportional to ESR).

Features of Low-Resistance Multi-Element MEGACAP

• Achieves high capacitance while minimizing product height and electrical resistance, through a horizontally arranged multi-element structure of MLCCs and optimized metal terminal materials.
• Excellent resistance to mechanical stress and thermal shock due to the metal frame structure.

If cracks occur in the ceramic body and moisture penetrates into them, the risk of short-mode failure increases significantly. Particular care is required in applications such as the following:

• Equipment constantly exposed to vibration or mechanical shock
• Equipment susceptible to frequent drop impacts
• Manufacturing processes where significant board flexure stress is applied during handling

TDK offers five series of high-reliability MLCCs designed to reduce the risk of short-mode failures caused by board flexure. We invite you to select the product from each series that best matches your application to help enhance the overall reliability of your design.