Multilayer Capacitor Layout for Low-Inductance Board Decoupling
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Solution Overview
Problem
Existing multilayer capacitors face challenges in high-speed environments due to increased current demands and miniaturization needs, requiring improved performance and reduced footprint, while traditional designs struggle with parasitic inductance and uniform connections to circuit boards.
Innovation Solution
A multilayer capacitor design featuring alternating dielectric and internal electrode layers with offset lead tabs, allowing for a compact, unitary package with reduced inductance and improved connectivity, enabling direct power ground connections and reduced size on circuit boards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional multilayer capacitor designs are used, then the capacitor can be manufactured with standard processes, but the parasitic inductance is high and decoupling performance is poor in high-speed environments
Solution Approach 1:
The patent applies asymmetry by offsetting the lead tabs from the center of the internal electrode layers. The lead tabs are positioned at different locations on adjacent electrode layers, creating an asymmetric configuration that reduces the loop area for current flow. This asymmetric arrangement directly reduces parasitic inductance and improves decoupling performance in high-speed environments.
Solution Approach 2:
The patent utilizes the vertical dimension by stacking multiple internal electrode layers with alternating polarities. The lead tabs extend in the vertical direction from the stacked layers, and external terminals are formed on both top and bottom surfaces. This three-dimensional arrangement reduces current path length and parasitic inductance compared to traditional planar designs.
2Area of stationary object
If capacitor size is reduced to meet miniaturization needs, then the footprint on circuit board is smaller, but maintaining low inductance and uniform connections becomes more difficult
Solution Approach 1:
The patent merges multiple internal electrode layers into a single unitary capacitor body through co-firing. The stacked dielectric layers and internal electrode layers are formed as one integrated structure, ensuring uniform connections and consistent electrical characteristics throughout the compact component. This merging maintains connection reliability while achieving miniaturization.
Solution Approach 2:
The patent transitions from a two-dimensional planar layout to a three-dimensional stacked configuration. Multiple electrode layers are arranged vertically with lead tabs extending in the vertical dimension, allowing the capacitor to maintain low inductance and uniform connections within a smaller horizontal footprint on the circuit board.
3Ease of manufacture
If lead tabs are positioned at the center of internal electrode layers, then manufacturing is simplified, but the inductance is maximized and decoupling performance is reduced
Solution Approach 1:
The patent deliberately introduces asymmetry by offsetting lead tabs from the center position of the internal electrode layers. The lead tabs are positioned at asymmetric locations on adjacent electrode layers, which increases manufacturing complexity but dramatically reduces the current loop area and parasitic inductance, improving decoupling performance.
Solution Approach 2:
The patent changes the positional parameter of the lead tabs from centered to offset positions. This parameter change in lead tab location optimizes the electrical characteristics by reducing parasitic inductance, accepting the trade-off of increased manufacturing complexity for superior high-speed performance.
Data Source
AI summary
The present invention is directed to a multilayer capacitor and a circuit board containing the multilayer capacitor. The capacitor includes a main body containing a first set of alternating dielectric layers and internal electrode layers and a second set of alternating dielectric layers and internal electrode layers. Each set contains a first internal electrode layer and a second internal electrode layer wherein each layer includes a top edge, a bottom edge opposite the top edge, and two side edges that define a main body of the layer. Each layer contains at least one lead tab extending from the top edge of the main body of the layer and at least one lead tab extending from the bottom edge of the main body of the layer wherein the lead tabs are offset from the side edges of the main body of the layer. In addition, external terminals are electrically connected to the internal electrode layers wherein the external terminals are formed on a top surface of the capacitor and a bottom surface of the capacitor opposing the top surface of the capacitor.