Today, I will share with you how to check whether the design of the PCB is correct. After the wiring of the PCB is completed, it is necessary to check the design rules of the circuit board to ensure that the circuit board meets the design requirements and all networks have been correctly connected. Commonly used inspection items in PCB design rule inspection are as follows:
- Check the distance between line and line, line and component pad, line and via, component pad and via, via and via and decide if the distance is reasonable, and whether it meets the production requirements.
- Modify the undesirable lines.
- Check to see if there is any separate ground wire for analog circuit and digital circuit
- Are the graphics (such as icons and annotations) added to the PCB board will cause signal short circuit.
- Is the outer frame edge of the power ground layer in the multilayer circuit board reduced? Such as the copper foil of the power ground layer is exposed, which may cause a short circuit.
- Are the width of the power line and the ground line appropriate, whether the power supply and the ground line are tightly coupled? And Is there a place to widen the ground line in the middle?
- Whether the best measures have been taken for the key signal lines, such as the shortest length, protection lines, input lines and output lines are clearly separated.
- Whether there is a process line on the PCB, whether the solder mask meets the requirements of the production process, whether the solder mask size is appropriate, and whether the character logo is pressed on the device pad.
Design rule inspection results can be divided into two types: one is Report output, which generates inspection result reports; the other is online inspection, which is to verify the electrical rules and wiring rules of the circuit board during the wiring process.
PCB rules include electrical rules, wiring, layout rules, high-speed circuit design rules, signal integrity and other rules. Through the study of this chapter, I have a detailed understanding of the design rules of the circuit board, and lay the foundation for the production of high-efficiency PCB.