Why are some PCB wiring strictly crossed on both sides?

bigbat

Why are some PCB wiring strictly crossed on both sides? [Copy link]

I have seen that some PCBs have strictly double-sided crossing wiring. Is there any purpose for this?

Just like this picture, Top is horizontal and Button is vertical.

lcofjp

If you don't cross it, you can't spread it out at all. If you don't believe it, you can try it yourself

philips_lu

For low-speed signals (except weak signals), you can lay them however you like, and generally it will not have much impact. But for high-speed signals or when strong and weak signals are mixed together, you need to pay special attention to the crosstalk between signals and the impact of external signals on the internal. At this time, horizontal and vertical lines are more important, but you should not blindly pursue horizontal and vertical lines. Too many vias have a great impact on high-speed signals! Of course, there is also a possibility that there are only two layers of boards, there are more routings, and the layout is unreasonable. If you don’t use horizontal and vertical lines, you simply can’t lay the lines properly.

maychang

Circuit boards have gradually developed from single-sided boards (insulating boards with copper foil on only one side) to double-sided boards (insulating boards with copper foil on both sides).

In theory, for a single-sided board, there is a possibility that wiring cannot be routed.

For a double-sided board, as long as the lines on one side of the board are horizontal and the lines on the other side are vertical, theoretically it can always be laid out.

qwqwqw2088

Since it is called "a strict two-sided cross"

It can be seen that there are quite a lot of vias used, so I suspect it is automatic wiring.

bigbat

This kind of wiring was very common in the early plug-in era. I have seen 286 computer motherboards and 386 motherboards with this kind of wiring, but it is not common after the "486". So I suspect that this kind of wiring should not be suitable for high-speed boards.

qwqwqw2088

This is how digital circuits are routed

The address lines, data lines, and control lines are all the same thickness, and they are also plug-in devices, so this circuit board is a product from the 1990s.