PCB board large area filling, PCB board jumper and high-frequency wiring
The purpose of large-area filling on PCB is to dissipate heat, and the other is to reduce interference by shielding. To avoid the copper film falling off due to the gas generated by PCB due to the heat generated during welding, a window should be opened on the large-area filling, whICh makes the filling grid. The use of copper coating can also achieve the purpose of anti-interference, and copper coating can automatically bypass the bonding pad and connect the ground wire.
PCB board jumper
In the design of single sided PCB boards, when some copper films cannot be connected, the common practice is to use jumper wires. The jumper wire lengths should be selected as follows: 6mm, 8mm and 10mm.
high frequency wiring of PCB board
1) Reasonable selection of layers
Using the middle inner plane as the power and ground layers can play a shielding role, effectively reduce the parasitic inductance, shorten the signal line length, and reduce the cross interference between signals. Generally, the noise of the four layer board is 20 dB lower than that of the two layer board.
2) Routing mode
The routing must turn at an angle of 45 °, which can reduce the transmission of high-frequency signals and mutual coupling.
3) Routing length
The shorter the routing length, the better. The shorter the parallel distance between two lines, the better.
4) Number of vias
The less the number of vias, the better.
5) Inter layer wiring direction
The wiring direction between layers should be vertical, that is, the top layer is horizontal and the bottom layer is vertical, so as to reduce the interference between signals.
Adding grounded copper coating can reduce the interference between signals.
7) Land parcel
Packet ground processing of important signal lines can significantly improve the anti-interference ability of this signal. Of course, it can also packet ground processing of interference sources so that they cannot interfere with other signals.
8) Signal line
The signal wiring shall not be looped, and shall be wired in daisy chain mode.
9) Decoupling capacitor
A decoupling capacitor is bridged at the power supply end of the integrated circuit.
10) High frequency choke
Digital ground, analog ground and other common ground wires shall be connected with high-frequency choke devices, which are generally high-frequency ferrite beads with wires through the central hole.