Monolithic Ceramic Capacitor ESR Control via Resistive Electrodes
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Solution Overview
Problem
Monolithic ceramic capacitors face challenges in balancing reduced equivalent series inductance (ESL) and equivalent series resistance (ESR) to prevent impedance mismatching and noise absorption issues in high-frequency applications, with existing methods for controlling ESR being cumbersome and limited in effectiveness.
Innovation Solution
A monolithic ceramic capacitor design featuring external terminal electrodes with a resistive component and internal electrodes arranged to optimize lead-out portions, allowing for controlled ESR adjustment while maintaining low ESL, by varying the width-direction size of lead-out portions relative to capacitance portions and using metal oxide materials in the resistive components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ESR of a monolithic ceramic capacitor is reduced too much by widening and shortening current paths or increasing the number of ceramic layers and internal electrodes, then the capacitance increases and ESL decreases, but impedance mismatching occurs and damped oscillation (ringing) is likely to occur
Solution Approach 1:
The patent applies parameter changes by introducing a resistive component in the external terminal electrodes with a specific resistivity range (10^-6 to 10^-3 ohm·cm) and controlling its thickness (1-50 μm). This changes the electrical parameters of the terminal electrodes to increase ESR to an optimal level, preventing impedance mismatching and ringing while maintaining adequate capacitance and low ESL characteristics.
2Object-affected harmful factors
If the ESR is increased to prevent impedance mismatching and ringing, then noise absorption capability deteriorates and the decoupling effect is reduced
Solution Approach 1:
The patent optimizes the resistive component parameters (resistivity between 10^-6 to 10^-3 ohm·cm and thickness of 1-50 μm) to achieve a balanced ESR value that prevents impedance mismatching and ringing while maintaining adequate noise absorption capability. This parameter optimization ensures the capacitor functions effectively as both a decoupling element and a noise filter.
Solution Approach 2:
The external terminal electrodes are constructed as composite structures combining resistive materials (such as ITO, IZO, or ZnO-based transparent conductive oxides) with conductive materials. This composite structure allows the electrodes to provide both the resistive component needed for preventing ringing and the conductive pathways necessary for noise absorption and decoupling functions.
3Reliability
If existing methods are used to control ESR by adjusting resistive paste composition or thickness, then ESR can be adjusted, but the manufacturing process becomes cumbersome and other factors such as reactivity with internal electrodes or fixing strength are adversely affected
Solution Approach 1:
The patent specifies optimal parameter ranges for the resistive component (resistivity: 10^-6 to 10^-3 ohm·cm, thickness: 1-50 μm) that balance ESR control with manufacturing ease. These parameter specifications provide clear manufacturing guidelines that avoid the need for complex process adjustments while achieving the desired ESR values.
Solution Approach 2:
The use of transparent conductive oxide materials (ITO, IZO, ZnO-based compounds) as the resistive component provides inherent advantages in manufacturing. These materials offer good reactivity with internal electrodes, adequate fixing strength, and controllable resistivity through composition adjustment, simplifying the manufacturing process compared to traditional resistive pastes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively increases ESR while maintaining ESL at a low level, facilitating better noise absorption across a broad frequency band and improving manufacturing efficiency by simplifying the adjustment of resistive components, thus addressing the limitations of previous methods.
Implementation Method 1
external terminal electrodes including a resistive component... facilitating control of the equivalent series resistance (ESR)
Implementation Method 2
using metal oxide materials in the resistive components
Data Source
AI summary
In a monolithic ceramic capacitor, the size of end surfaces of a capacitor body in a two-dimensional surface in which ceramic layers extend is greater than the size of side surfaces in the two-dimensional surface in which the ceramic layers extend. External terminal electrodes include a resistive component. In each of first to fourth internal electrodes, a width-direction size of a lead-out portion is less than a width-direction size of a capacitance portion. The lead-out portions of the first and third internal electrodes and the lead-out portions of the second and fourth internal electrodes are arranged so as to partially overlap each other or not to overlap each other.