The design flow of the multilayer PCB circuit board is basically the same as that of the ordinary pcb board. The difference is that the intermediate signal layer is required to be routed and the inner layer is divided. In general, the design of the multilayer PCB circuit board is basically Divided into the following steps. This article will briefly introduce these steps.
The planning of the circuit board is mainly to plan the physical size of the pcb board, the package form of the components, the component mounting method, and the layer structure, that is, the single layer board, the double layer board and the multi-layer board.
The working parameter setting mainly refers to the working environment parameter setting and the working layer parameter setting. Correct and reasonable setting of pcb environment parameters can bring great convenience to the design of the circuit board and improve work efficiency.
Component layout and adjustment, after the current period of work is ready, you can import the network table into the pcb, or you can import the network table directly by updating the pcb in the schematic diagram. Readers who have used protel dxp know that the system comes with automatic layout, but the effect of automatic layout is often not ideal. Generally, manual layout should be used, especially for complex circuits and components with special requirements. Component layout and adjustment is a relatively important task in the pcb design, which directly affects the operation of the subsequent wiring and the division of the inner layer.
The definition and setting of the middle layer of the PCB circuit board, the operation focus is to set a specific layer structure in the layer stack manager of the software, mainly to set the number of intermediate signal layers and inner layers, upper and lower structures, and the like.
Internal electrical layer division, usually the inner layer, often more than one power network, often need to divide the internal power layer into several isolated areas, and connect each area to a specific power network, which is a multi-layer board and common The biggest difference between boards is also an important part of multi-layer board design. The structure of the inner electric layer segmentation often directly affects the traces of the power supply and the ground grid, and is affected by the layout and routing of components.
Wiring rule setting, mainly to set various specifications of circuit wiring, wire width, parallel line spacing, safety spacing between wires and pads, and via size, etc., regardless of the wiring method, wiring rules are essential One step, good wiring rules can ensure the safety of the circuit board routing, and meet the production process requirements, saving costs.
Wiring and adjustment, the system provides automatic wiring, but often can not meet the requirements of the designer, in practical applications, designers often rely on manual wiring, or part of automatic routing combined with manual interactive wiring to complete the wiring work. Special attention should be paid to the layout and wiring and the fact that the PCB circuit board has an internal electrical layer. Although the layout and wiring are sequential, in the design engineering, the layout of the circuit board is often adjusted according to the needs of wiring and internal electrical layer division, or Adjusting the wiring according to the layout, they are a process of mutual consideration and mutual adjustment.
Other auxiliary operations, such as copper and teardrop operations, as well as document processing such as report output and save disk printing, can be used to check and modify the PCB board, and can also be used as a list of purchased components.