Asymmetric Lead MLCC Design for Low ESL and High Capacitance
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Solution Overview
Problem
Multilayer ceramic capacitors (MLCCs) face challenges in achieving low equivalent series inductance (ESL) while maintaining high capacitance, which can impede the functionality of bypass capacitors in compact, multifunctional electronic devices.
Innovation Solution
The design of a multilayer ceramic capacitor with specific lead portion lengths and configurations, where Mb > Mt, and satisfying the relationships 1.69≤Ts/(Mt+Mb)≤17.75 and 0.0282≤Mb/Ts≤0.2958, along with perpendicularly stacked internal electrodes and external electrodes, minimizes ESL and maximizes capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the lead portions are made longer to increase capacitance, then the capacitance increases, but the equivalent series inductance (ESL) increases
Solution Approach 1:
The patent applies asymmetry by making the lead portions extend beyond the electrode plates (Mb > Mt), creating an asymmetric configuration that optimizes the balance between capacitance and ESL. This asymmetric design allows the lead portions to contribute to capacitance while minimizing their negative impact on inductance by extending them preferentially in one direction.
Solution Approach 2:
The patent utilizes the third dimension by extending lead portions in the thickness direction of the ceramic body rather than only in the plane direction. This dimensional change allows the lead portions to contribute to capacitance through their extended length while their vertical orientation minimizes the loop area, thereby reducing ESL.
2Quantity of substance
If the internal electrodes are made larger to increase capacitance, then the capacitance increases, but the device size increases
Solution Approach 1:
The patent exploits the thickness direction (third dimension) to extend the lead portions, allowing increased capacitance without increasing the planar footprint. By extending leads vertically through the ceramic body thickness, the design achieves higher capacitance in a compact form factor.
Solution Approach 2:
The patent changes the geometric parameters by establishing specific ratio relationships (Mb > Mt, and Mb/Ts within 0.0282-0.2958) to optimize the configuration. These parameter changes allow maximization of capacitance within constrained dimensions by carefully controlling the relative lengths and positions of electrode components.
3Quantity of substance
If the lead portions extend significantly beyond the electrode plates, then the capacitance increases, but the risk of short circuits and defective cutting increases
Solution Approach 1:
The patent establishes optimized parameter ranges (Mb > Mt and 0.0282≤Mb/Ts≤0.2958) that balance capacitance enhancement with reliability. These parameter constraints prevent excessive lead extension that would cause manufacturing defects while still achieving sufficient capacitance increase.
Solution Approach 2:
The patent applies different extension lengths to different portions of the lead structure (Mb for capacitance contribution versus Mt for structural stability), creating local quality variations that optimize both capacitance and reliability. The lead portions extending beyond electrode plates provide capacitance while the constrained extension ratio prevents excessive vulnerability.
Data Source
AI summary
A multilayer ceramic capacitor includes a ceramic body including a dielectric layer and first and second internal electrodes alternately disposed with the dielectric layer interposed therebetween. The first internal electrode includes a first electrode plate and a first lead portion exposed to an external surface of the ceramic body and the second internal electrode includes a second electrode plate and a second lead portion exposed to an external surface of the ceramic body. The relationship Mb>Mt may be satisfied, where Mb is a length of the first and second lead portions extending from the first and second electrode plates to a mounting surface of the ceramic body to which the first and second lead portions are exposed and Mt is a length from the first and second electrode plates to a surface of the ceramic body opposing the mounting surface.