Flex Crack Safety for MLCCs

Manufacturer: Kemet
Products: MLCC

Kemets Flex Crack Mitigation Solutions
With design advances in multilayer ceramic capacitors (MLCC), has come a new challenge for the design engineer, and that has been a Low IR or short circuit situation due to small cracks close to the end terminations of the ceramic capacitor. This is attributed to board flexing, however, board Flex cannot be eliminated by the capacitor manufacturers. Kemet has taken steps to develop a product portfolio that offers the engineer a number of different reliability solutions, should the problem occur. The Kemet Flex mitigation portfolio, consists of 4 solutions which are

Floating Electrode - FE Cap
The internal construction drawing (below) shows that the electrodes are configured to form multiple capacitors in series within a single MLCC package. This does not only improve the capability to withstand higher voltages and improves the ESD performance. It also mitigates the risk of low-IR or short-circuit failures that can occur due to board flex.

Open Mode - Fail Open
This design greatly reduces the likelihood of a low-IR or short circuit condition in a board flex situation. During a flex to failure situation Kemets "Open-Mode" capacitor may experience a drop in capacitance but a short is unlikely because the crack won't typically cross opposing electrodes (this has been confirmed in extensive testing). Since there won't be any current leakage associated with a typical "Open-Mode" flex crack there is no localized heating and, therefore, no chance for a catastrophic and potentially costly failure event.

Flex Term - FT Cap
The FT-CAP is a surface mount Multilayer ceramic capacitor that incorporates a unique and flexible termination system. Integrated with Kemets standard termination materials, a conductive epoxy is utilized between the conductive metallization and nickel barrier finish in order to establish pliability while maintaining terminal strength, solderability and electrical performance. This technology directs board flex stress away from the ceramic body and into the termination area. As a result, this termination system mitigates the risk of low-IR or short-circuit failures associated with board flex.

Floating Electrode and Flex Term - FF Cap
This combines two of the technologies above, named FF cap, utilizing the Floating electrode construction, along with the flexible termination system with the advantages of. The CV offering will be the same as the FE Cap, but the addition of the flexible termination offers the design engineer a much more flex robust and reliable solution for MLCC products.

Specifications