PCB Blogger-China PCB Factory,HOYOGO

  In the PCB industry, manufacturers have many methods for PCB inspection. For example: signal injection method, substitution method, offline Inspection, online inspection, parameter test method, waveform observation method, visual inspection method, signal tracking method, AC short circuit method, separation test method, etc. The intelligent detection method of the circuit board needs to select the online test method according to the specific characteristics of the PCB board, in order to combine one or more processes, complement each other, and make comprehensive utilization. First, use the idea of virtual instruments on the PCB to establish related application software, that is, implement various functions of traditional instruments through software, including oscilloscopes, signal generators, and various mathematical processes on the collected data. During the test, the digital signal is given by the test software. Then, the PCB test system will have new design ideas. Adopt the desi

  In PCB design, considering the signal quality control factors, the general principle of PCB stack-up is as follows: 1. The second layer adjacent to the component surface is the ground plane, which provides a device shielding layer, and the top-level wiring provides a reference plane. 2. All signal layers are as close as possible to the ground plane to ensure a complete return path. 3. Please try to avoid two signal layers directly adjacent to reduce crosstalk. 4. The main power supply is as close as possible to form a plane capacitor to reduce the power plane impedance. 5. Taking into account the symmetry of the laminated structure, it is beneficial to the warpage control in the plate making process. The above are the general principles of stack-up design. In the actual stack-up of layered design, the circuit board designers can reduce the distance between the corresponding wiring layer and the reference plane by increasing the distance between adjacent wiring layers, thereby control

  The heat resistance of HDI board is an important item. The thickness of HDI boards is getting thinner and thinner, and the requirements for heat resistance are getting higher and higher. The advancement of lead-free process has also increased the requirements for the heat resistance of HDI boards, and because HDI boards are different from ordinary multilayer through-hole PCB circuit boards in terms of layer structure, the heat resistance properties of the two is different. The heat resistance defects of HDI board are mainly break and delamination. So far, based on the heat resistance test experience of various materials and HDI boards, it is found that the areas with the highest probability of HDI board break are the areas above the dense buried holes and the areas below the large copper surface. Heat resistance refers to the ability of the PCB to resist the thermo-mechanical stress generated during the soldering process. The delamination mechanisms of PCB in heat resistance test gen

  Did you know that the distributed capacitance of the printed circuit board layout will work at high frequencies. When the length is greater than 1/20 of the corresponding wavelength of the noise frequency, an antenna effect will occur, and the noise will extend the emission through the layout. If there is a poorly grounded copper pour in the PCB, the copper pour becomes a noise propagation tool. So, in high-frequency circuits, do not think that the ground wire is grounded. This is the "ground wire". Be sure to punch holes in the wiring with a pitch less than  λ /20 to "good ground" with the ground plane of the multilayer board.  If the copper pour is handled properly, the copper pour not only has a larger current, but also plays a dual role of shielding interference. There are generally two basic methods for copper pour, which are large-area copper pour and copper grid. People often ask, is it better to pour copper over a large area or copper grid? But this is dif

Copper is used to interconnect components on the substrate. Although it is a good conductor material for patterning the conductive path of a printed circuit board, if exposed to the air for a long time, it will easily lose gloss due to oxidation, suffer corrosion and lose its solderability. Therefore, various technologies must be used to protect copper traces, vias, and plated through holes. These technologies include organic paint, oxide film, and electroplating. Organic paint is very simple to apply, but due to changes in its concentration, composition and curing cycle, it is not suitable for long-term use. It will even cause unpredictable deviations in weldability. The oxide film can protect the circuit from corrosion, but cannot maintain solderability. Electroplating or metal etching technologies are standard operations to ensure solderability and protect circuits from corrosion, and play an important role in the manufacture of single-sided, double-sided and multilayer printed circ

  Generally, the requirements for structure design and technology manufacturing of multi-layer electric boards are very high. The more layers, the more difficult it is, and it is suitable for more complex circuits. So what are the advantages of using multilayer circuit boards. The advantages of using multilayer boards are: 1. High assembly density and small size; 2. Shorten the connection between electronic components and increase the signal transmission speed; 3. Convenient routing; 4. For high-frequency circuits, add a ground layer to make the signal line form a constant low impedance to the ground; 5. Good shielding effect. However, the more layers, the higher the cost, the longer the processing cycle, and the more troublesome the quality inspection is. Our common computer boards usually use 4-layer boards or 6-layer boards, but now there are more than 100 layers of practical printed circuit boards. The difference between the 6-layer board and the 4-layer board is in the middle, tha

  PCB plays an extremely important role in electronic products, and it is the core part of electronic products. PCB has grown from single-layer to double-sided boards, multilayer boards and flexible boards, and continues to develop towards high precision, high density and high reliability. By continuously reducing the size, reducing costs, and improving performance, printed circuit boards will still maintain a strong vitality in the future growth of electronic products. 1. Manufacturability: With modern management, standardized, scoped and automated production can be carried out to ensure equal product quality. 2. High-density: For decades, with the improvement of integrated circuit integration and placement technology, high-density printed circuit boards can be developed. 3. High-reliability: Through a series of inspection, testing and aging test, the permanence and reliability of the PCB can be guaranteed. The service life of PCB is usually 20 years. 4. Testability: A relatively comp