Pinsheng Electronics Co.,Ltd
1. The Location of the Display
In general, when screens of resistors, capacitors, tubes, etc. are placed, do not use four directions. This will result in debugging, maintenance, and welding. Look at the screen printing and it is very tiring (the board must be turned in several directions). .
Therefore, it is recommended to place it in two directions as shown in the figure below. In this way, the silk screen will be viewed in a very respectable way.
2.Try not to hit the silk screen on the hole
As shown in the figure below, the hole is hit in the 8 word. After the board is returned, you can't tell whether it is R48 or R49.
3.The Direction of reading silk screen should be consistent with the direction of use.
As shown in the figure below, the direction of reading of the screen printing is consistent with the direction of use of the chip, mainly when welding, reducing the probability of welding reverse.
Others, such as electrolytic capacitors, may also not follow this recommendation because you can indicate positive and negative polarity.
4.Do not press silk screens on high-speed signal lines (eg, clock lines, etc.)
This suggestion is for high-speed signal lines on the top or bottom layer, because these signal lines can be considered as microstrip lines.
The speed of the signal running on the microstrip line (phase velocity) is related to the medium. If the silk screen is pressed to the line, as shown in the figure below, the medium will become inhomogeneous, causing the phase velocity to change and eventually appearing as an impedance discontinuity. , affect the signal quality.
Of course, the signal line in the inner layer will not have such a problem.
5.The pin number should be clearly marked on the silk screen.
6.Special packaging silk screen.
For special packages such as BGA and QFN, the size of the silk screen should be exactly the same as the size of the chip(as below pictures). Otherwise, it will be difficult to align and affect the soldering.
7.Mounting hole silk screen.
Here, the silk screen of the screw is added near the mounting hole, and the length and the total number of screws are marked to facilitate the installation.
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