Printed Circuit Board Vibration Research Articles

Analysis of Typical PCB Vibration Characteristics Based on Modal Simulation and Experiment

This study combines simulation and experimental methods to explore the vibration characteristics of a servo controller printed circuit board (PCB). CREO is used to build a simulation model based on PCB structure analysis. ANSYS was used to perform finite element simulation analysis of vibration characteristics. The hammering method is used to perform circuit board modal experiments. By comparing the results of simulation and experimentation, the PCB dynamic characteristics are analyzed. It was found that the fixed frequency error of the simulation and the experiment is within 6%, and the first three mode shapes are consistent. Hence, it is suggested to use the simulation model for the subsequent vibration reliability analysis of the electronic product.

A Methodology for Predicting Acoustic Noise From Singing Capacitors in Mobile Devices

Multilayer ceramic capacitors (MLCCs) connected to a power distribution network (PDN) can create acoustic noise through a combination of the power rail noise at the MLCCs and the piezoelectric effect of the capacitor's ceramic material. The deformation of the MLCCs brought on by power supply noise creates vibrations which cause the printed circuit board (PCB) to vibrate and generate the audible acoustic noise. In the following paper, a simulation methodology is presented to analyze the acoustic noise created by MLCCs on a PCB. A simulation model for the PCB vibration modal response is built and the modal superposition method is used to analyze the harmonic response of the PCB excited by the capacitor. By multiplying the measured power noise spectrum on the MLCC with the simulated deformation of the PCB found from the harmonic response analysis, the total response is obtained. Simulated results show a good correlation with the measured acoustic noise. The proposed method shows promise for analyzing and predicting the acoustic noise from singing capacitors.

Simulation Methodologies for Acoustic Noise Induced by Multilayer Ceramic Capacitors of Power Distribution Network in Mobile Systems

In this article, multilayer ceramic capacitors (MLCCs) induced acoustic noise is studied through simulation investigation of the vibration behavior of the printed circuit board (PCB). The board vibration theory is briefly summarized to understand the key parameters influencing intrinsic board vibration properties. The identified key parameters are the thickness, mass density, and Young's modulus of each board layer. To accommodate the parameter variations in real board fabrication process, a statistical simulation model for PCB vibration modal response is proposed. The simulation results have shown good correlation with the measurement. The sensitivity analysis of board vibration properties to the identified parameters of each layer has also been conducted through simulation. Based on the derived intrinsic board vibration properties, the PCB vibration behavior with capacitor as forced excitation is further analyzed through modal superposition. The simulated results also exhibit good correlation with measurement. With the proposed simulation methods, engineers can evaluate the board vibration behavior at early design stage and some design guidelines for placing MLCCs can be derived to reduce acoustic noise.

Measurement Methodologies for Acoustic Noise Induced by Multilayer Ceramic Capacitors of Power Distribution Network in Mobile Systems

In this article, acoustic noise of printed circuit board (PCB) introduced by multilayer ceramic capacitors (MLCCs) on power distribution network (PDN) is studied. The correlation of PDN power rail noise, MLCCs and PCB dynamic characteristics, and PCB acoustic noise is demonstrated on a real mobile product through electrical, vibrational, and acoustic measurements. Two measurement methodologies are proposed to identify the problematic MLCCs on the power rail. One method analyzes the board and MLCCs vibration properties with the external electrical signal applied on the power rail on a product board. Other measurement detects the problematic MLCCs based on the coherence value between the power rail signal during product operation and MLCC vibration characteristics. By replacing the identified original MLCCs with low acoustic noise ones, the PCB vibration is clearly reduced. With the MLCCs’ influence on PCB vibration studied, a measurement methodology is also proposed to analyze the PCB intrinsic vibration properties. The intrinsic modal response of PCB is applied to predict the MLCC-induced PCB vibration. The obtained modal response can also provide design guidelines for MLCC placement to reduce the level of PCB vibration.

Analysis of the influence of soldering parameters on multi-layer ceramic capacitor vibration

Owing to their superior electrical performance, multilayer ceramic capacitors (MLCCs) are widely applied in a variety of electronic devices. The acoustic noise of MLCCs is an important factor to be considered when selecting MLCCs for specific applications, such as smart phones. This noise is directly related to the vibration of the printed circuit board (PCB) on which MLCCs are mounted. Therefore, to improve the noise and vibration characteristics, this paper investigated the effects of soldering parameters on PCB vibration. Based on the findings, a novel soldering method that reduces vibration is described.

Estimating the Dynamic Behavior of Printed Circuit Boards

The vibration analysis of printed circuit boards plays an important role in the reliability of packages. The Castigliano's theorem is employed to calculate the constrain stiffness of a preloaded beryllium-copper wavy spring, which acted as a board edge guide. The numerical results solved using the Castigliano's theorem are compared with the numerical results solved using the finite element method. Appropriate boundary conditions accompanied the differential quadrature method (DQM) to transform the partial differential equation into a discrete eigenvalue problem. The effects of electronic components and the constrained boundary conduction on the dynamic characteristics of a printed circuit board are investigated. Numerical results indicate the DQM model can solve the printed circuit board vibration efficiently.