Diagonal Electrode Pad Placement for MLCC Noise Reduction
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Solution Overview
Problem
Multilayer ceramic capacitors generate acoustic noise due to piezoelectric vibrations, causing discomfort, as these vibrations are transferred to printed circuit boards, and existing mounting structures do not effectively mitigate this noise.
Innovation Solution
A mounting circuit board design for multilayer ceramic capacitors with first and second electrode pads positioned diagonally opposed on the ceramic body, where the interval between pads and their ratio satisfy specific dimensions, along with asymmetric external electrode placement, to reduce vibration transfer and acoustic noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional mounting structures are used, then ease of manufacture is maintained, but acoustic noise increases due to vibration transfer
Solution Approach 1:
The patent applies asymmetry by positioning the first and second electrode pads at diagonally opposite corners of the printed circuit board rather than symmetrically. This asymmetric diagonal arrangement disrupts the vibration transfer path from the multilayer ceramic capacitor to the board, reducing acoustic noise while maintaining manufacturing simplicity through standard PCB layout techniques.
Solution Approach 2:
The patent transitions from conventional linear or adjacent electrode pad arrangements to a diagonal arrangement across the board. This dimensional change in pad positioning creates longer vibration transfer paths and reduces the efficiency of vibration transmission, thereby decreasing acoustic noise without complicating the manufacturing process.
2Object-affected harmful factors
If electrode pads are positioned to reduce vibration transfer, then acoustic noise decreases, but manufacturing precision requirements increase
Solution Approach 1:
The patent segments the vibration transfer path by placing electrode pads at diagonally opposite corners rather than adjacent to each other. This segmentation creates multiple intermediate structures (board material, solder joints, traces) that decouple the vibration transmission, reducing vibration transfer effectiveness while allowing standard manufacturing tolerances to be maintained.
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
Significantly decreases acoustic noise levels below 20 dB by optimizing the placement and dimensions of electrode pads and external electrodes, maintaining effective capacitance and reducing vibration transfer to the printed circuit board.
Implementation Method 1
Since the dielectric layers as described above have piezoelectricity and electrostriction, when a direct current (DC) voltage or an alternate current (AC) voltage is applied to the multilayer ceramic capacitors, piezoelectric phenomena are generated between the internal electrodes to cause the occurrence of vibrations.
Data Source
AI summary
A mounting circuit board of a multilayer ceramic capacitor includes a multilayer ceramic capacitor including a ceramic body in which a plurality of dielectric layers are stacked, an active layer including a plurality of first and second internal electrodes alternately exposed to both end surfaces of the ceramic body, having the dielectric layer therebetween, and first and second external electrodes extended from both end surfaces of the ceramic body to a portion of a lower surface thereof; and a printed circuit board having first and second electrode pads so that the first and second external electrodes are mounted thereon, wherein the first and second electrode pads are disposed in positions diagonally opposed to each other, based on the ceramic body.