For the setting of PCB circuit board wiring line width, there are two main issues to consider:
One is the magnitude of the current flowing. For example, for power lines, it is necessary to consider the current flowing when the circuit is working. If the current flowing is large, the wiring should not be too thin.
Actual measurement: Current carrying capacity of PCB circuit board traces and vias
The second is to consider the actual board manufacturing capacity of the circuit board factory. If the required current is very small (such as a signal line), it can be made thinner. Sometimes the PCB area is small and there are many components, so I want to trace the wires as thin as possible, but if it is too thin, the circuit board factory may not be able to make it, or it may not be able to make it but the defect rate will increase. This can be confirmed with the circuit board factory. As far as I know, the line width is 0.2mm, the line spacing is 0.2mm, and the general circuit board factory can do it. Not everything can be done with a line width of 0.127mm. The minimum line width standard in the industry should be 0.1mm. Follow-up with the development of technology may be more detailed.
As for the size of the via hole, you can also confirm it directly with the circuit board factory. After all, even if you design a PCB circuit board with a small-aperture via hole, the circuit board factory cannot do it, or it can be done but the cost is high. As far as I know, the outer diameter of 0.5mm and the inner diameter of 0.3mm can be made by basically all board factories.
1. The PCB circuit board needs to be a signal line with impedance, which should be set strictly according to the line width and line spacing calculated by the stack. Such as radio frequency signal ((conventional 50R control), important single-ended 50R, differential 90R, differential 100R and other signal lines, the specific line width and line spacing can be calculated through lamination (as shown in the figure below).
The PCB circuit board needs to be laminated with impedance
2. The designed line width and line spacing should consider the production process capability of the selected circuit board factory. If the line width and line spacing exceeds the process capability of the cooperative PCB manufacturer during design, unnecessary production costs will need to be added, and the worst will be resulting in a design that cannot be produced. Under normal circumstances, the line width and line spacing are controlled to 6/6mil, and the via hole selection is 12mil (0.3mm). Basically, more than 80% of PCB manufacturers can produce it, and the production cost is the lowest. The minimum line width and line spacing is controlled to 4/4mil, and the via hole is 8mil (0.2mm). Basically, more than 70% of PCB manufacturers can produce it, but the price is slightly more expensive than the first case, not too expensive. The minimum line width and line spacing is controlled to 3.5/3.5mil, and the via hole is 8mil (0.2mm). At this time, some PCB manufacturers cannot produce it, and the price will be more expensive. The minimum line width and line spacing is controlled to 2/2mil, and the via hole is selected to be 4mil (0.1mm. At this time, it is usually an HDI blind buried via design, which requires laser vias). At this time, most PCB manufacturers cannot produce it, and the price is the most expensive. of. The line width and line spacing here refer to the size between elements such as line-to-hole, line-to-line, line-to-pad, line-to-via, hole-to-pad, etc.
3. Set rules to consider design bottlenecks in design documents. If there is a 1mm BGA chip, if the pin depth is shallow, only one signal line needs to be run between the two rows of pins. It can be set to 6/6mil. The pin depth is deeper, and two lines need to be run between the two rows of pins. For the signal line, set it to 4/4mil; if there is a BGA chip of 0.65mm, it is generally set to 4/4mil; if there is a BGA chip of 0.5mm, the minimum line width and line spacing must be set to 3.5/3.5mil; if there is a BGA chip of 0.4mm Chips generally require HDI design. Generally, for design bottlenecks, regional rules can be set (see the end of the article for the setting method), the local line width and line spacing should be set smaller, and the rules in other places on the PCB should be set larger to facilitate production and improve the pass rate of the produced PCB.
4. It needs to be set according to the density of the PCB circuit board design. The density is small, the board is loose, and the line width and line spacing can be set to be larger, and vice versa. Routine can be set in the following steps:
① 8/8mil, choose 12mil (0.3mm) via hole.
②6/6mil, select 12mil (0.3mm) via hole.
③4/4mil, choose 8mil (0.2mm) for the via hole.
④3.5/3.5mil, choose 8mil (0.2mm) for the via hole.
⑤3.5/3.5mil, choose 4mil via hole (0.1mm, laser drilling).
⑥2/2mil, choose 4mil (0.1mm, laser drilling) for the via hole.
