TG circuit board PCB design
High-precision TG circuit board rapid proofing With the advancement of electronic technology, the complexity level and application range of PCB (printed circuit board) have been rapidly developed.
Those engaged in high-frequency PCB design must have the corresponding fundamental theory, and should also have a rich experience in manufacturing high-frequency PCBs. In other words, whether it is the drawing of the PCB schematic or the PCB design, it should be considered from the high-frequency working environment in which it is located, in order to design an ideal PCB.
This article mainly from the manual planning and wiring of high-frequency PCB, based on Protel 99 SE to stop some of the problems in high-frequency PCB design.
1 Planning design
Although Protel 99 SE has the function of automatic planning, it can not fully meet the working requirements of high-frequency circuits. It is often necessary to rely on the experience of PCB designers. Based on the detailed conditions, the manual planning method is used to optimize the position of local components. Separate automatic planning to complete the overall design of the PCB. Whether the planning is reasonable or not directly affects the product's life, stability, EMC (electromagnetic compatibility), etc., must be from the overall planning of the board, the wiring of the passability and PCB manufacturability, mechanical construction, heat dissipation, EMI (electromagnetic Interference), reliability, signal integrity and other aspects of comprehensive thinking.
Ordinary first place the components in the fixed position related to the mechanical size, then place special and large components, and finally place small components. At the same time, it is necessary to coordinate the wiring requirements, the placement of high-frequency components should be as compact as possible, the wiring of the signal lines should be as short as possible, thereby reducing the interference of signal lines.
High-frequency circuits are often highly integrated and have high wiring density. The use of multi-layer boards is both necessary for wiring and an effective means of reducing interference. Protel for Windows V1.5 can provide 16 copper layers and 4 power layers. Reasonable selection of layers can greatly reduce the size of the board, and can effectively apply the middle layer to set the shielding. It can better complete the grounding and can effectively The ground reduces the parasitic inductance, can effectively shorten the transmission length of the signal, and can greatly reduce the interspin interference between signals. All of these are beneficial to the robust operation of high-frequency circuits. When materials show the same kind of data, the four-layer board is 20dB lower than the noise of the double-panel, but the higher the number of layers, the more complicated the manufacturing process and the higher the cost. TG circuit board rapid prototyping，The less the lead bend between the pins of the high-speed circuit device, the better. The lead wire of the high-frequency circuit wiring is preferably a full-line, and the transfer machine can be used with a 45-degree fold line or a circular transfer machine. This request is only used to improve the fixing strength of the steel foil in the low frequency circuit, and satisfying this request in the high frequency circuit can reduce the external emission and mutual coupling of the high frequency signal.
When wiring with Protel, you can pre-set it in two places: one is scheduled to be routed in 45/90 Line or 90 ArcLine in the Track Mode submenu of the Options menu; the second is the RoutingPasses dialog opened in the Setup Autorouter item of the Auto menu. The box selects Add Arcs so that the corners are rounded when the automatic routing is completed.
Buried/blind hole multi-layer board process and technology
Ordinary use of the second lamination method. which is:
Unwinding---constituting the core board (corresponding to a conventional double-panel or multi-layer board)---lamination--- The following process is the same as the conventional multilayer board.
(Note 1): The constituent core plate refers to a double-panel or multi-layer plate formed according to a conventional method, and a buried/blind-hole multilayer plate is constructed as required. If the thickness-to-diameter ratio of the hole of the core plate is large, the hole-blocking treatment should be stopped to ensure its reliability. TG circuit board rapid prototyping
Multi-layer boards are now used on both the motherboard and the graphics card, greatly increasing the area that can be routed. The multi-layer board is provided with more single or double-sided wiring boards, and is pressed after an insulating layer is placed between each board.
The number of layers of the PCB board represents several layers of independent wiring layers. Usually, the number of layers is even and the outermost surface layer is included. The common PCB board is generally a 4-8 layer structure. The number of layers of many PCB boards can be seen by viewing the cut surface of the PCB board.
But in practice, no one can have such a good eye. So, let's teach you a way.
The circuit connection of the multi-layer board is through the buried hole and the blind hole technology. The main board and the display card mostly use the 4-layer PCB board, and some of the boards are 6, 8 layers and even 10 layers of the PCB board.
To see that there are several layers of the PCB, it can be identified by looking at the via hole. Since the 4-layer board used on the main board and the display card is the 1st and 4th layer traces, the other layers have other uses (ground line). And power). Therefore, like the double-layer board, the guide hole will penetrate the PCB board. If some of the vias are on the front of the PCB, but not on the back, then it must be a 6/8 layer. If the same guide hole can be found on the front and back of the PCB board, it is naturally a 4-layer board. High-definition TG circuit board.
Shenzhen Juding Circuit Technology Co., Ltd. specializes in: PCB circuit board manufacturing, PCB board proofing, HDI board, TG board, mixed pressure board, thick copper foil board, impedance board, Rogers board, soft and hard board, metal substrate, etc. A special material or process PCB board 1-34 laminate production and production. Welcome to consult customers for more details!