Introducing Flex "Fail-Open" Capabilities for MLC Chip Capacitors

Higher capacitance offerings in ceramic MLC capacitors is not restricted to increasing the capacitance capability of the smaller 0402 and 0603 chip sizes, but expanding the capacitance capabilities of the 0805, 1206, 1210, and 1812 chip sizes. These larger chip sizes present the manufacturer a dilemma as the ceramic capacitor is a “rock-solid” performer with excellent reliability when these devices are not cracked; but these larger devices have a greater tendency to crack. Once the ceramic capacitor cracks, it is susceptible to moisture and ionic ingress and subsequent failure that could lead to a “shorted” condition. This condition can create a large amount of concentrated heat on the printed circuit board. Because the flex crack is absolutely predictable as to where the crack is initiated, design modifications can be implemented to allow the crack to propagate into “safe regions” within the structure where the failure mode becomes more benign as an “open” condition.