In this article we explain the PCB design process step by step. We also provide an overview of the different types of boards available.
PCB DESIGN FLOW CHART
PRELIMINARY PREPARATION
This includes preparing footprint libraries and schematics.
Schematic
Analyze how to design the schematic, you can search for references to ensure accuracy, this step will affect the subsequent production of the PCB.
Design schematic components and build your own component library. If you encounter an uncertain circuit or component in your design, you can perform circuit simulation.
PCB STRUCTURE DESIGN
In this step, according to the determined circuit board size and various mechanical positioning. draw the PCB surface in the PCB design environment, and place the required connectors, buttons, screw holes, assembly holes, etc. according to the positioning requirements.
And fully consider and determine the wiring area and non-wiring area (such as how much area around the screw hole belongs to the non-wiring area).
GUIDE NETLIST
It is recommended to import the board frame before the netlist. Import the board frame in DXF format or the board frame in emn format
RULE SETTING
Reasonable rules can be set according to the specific PCB design. The rules we call are the constraint manager of PADS. Through the constraint manager, the line width and safety distance are constrained in any link in the design process. Where the constraints are not met During subsequent DRC detection, it will be marked with DRC Markers.
The general rule setting is placed before the layout, because sometimes some fanout work needs to be completed during the layout. so the rules must be set before the fanout. When the design project is large, the design can be completed more efficiently.
General settings are:
Default line width.
Select and set up vias
Line width and color settings for important signals and power supplies.
Layer settings.
PCB LAYOUT
The general layout is carried out according to the following principles.Reasonable division according to electrical performance.
Circuits that complete the same function should be placed as close as possible, and each component should be adjusted to ensure the most concise connection.
For components with large mass, the installation location and installation strength should be considered.
The heating element should be placed separately from the temperature sensitive element, and thermal convection measures should also be considered if necessary.
The I/O driver is as close as possible to the edge of the printed board and to the lead-out connector.
The clock generator should be placed as close as possible to the device that uses the clock.
A decoupling capacitor needs to be added between the power input pin of each integrated circuit and the ground.
When board space is tight, a tantalum capacitor can be added around several integrated circuits.
A discharge diode should be added to the relay coil.
Layout requirements should be balanced, dense and orderly.
WIRING
Routing is the most important process in the entire PCB design. This will directly affect the performance of the PCB board.
Carefully adjust wiring for optimum electrical performance. Next is beauty. If your wiring is messy, it will bring great inconvenience to testing and maintenance. The wiring should be neat and uniform, and not criss-cross without any rules.
Wiring optimization and silk screen
Silkscreen, be careful not to be blocked by the device or removed by vias and pads. At the same time, when designing, face the component surface, and the words on the bottom layer should be mirrored to avoid confusing the level.
CHECK
Before light painting, it needs to be checked, including the requirements of principle, design, production and other links.
OUTPUT LIGHT PAINTING
Before the light-painting output, it is necessary to ensure that the veneer is the latest version that has been completed and meets the design requirements. The light-painting output files are respectively used for the board factory, the steel mesh factory to make the steel mesh, and the welding factory to make process documents.
LIGHT PAINTING REVIEW
After outputting the light painting, it is necessary to perform the light painting inspection.
Wonderful PCB You can send us your requirements first, we will reply you as soon as possible.
English