In order to suppress noise ability, earthing and power of graphics should be parallel to the direction of data flow.
Multilayer PCB may take several as shielding layer, power supply layer and ground layer can be regarded as shielding layer, note that the general ground inner or outer layer and the power supply design.
Digital and analog area as far as possible in isolation, and in the digital and analog to the separation of the grounding and power supply layer. Printed wiring layout should be as short as possible; Unified components to every address line or cable should be kept as long; When the circuit wire for high frequency circuit or dense, printed wiring corners should be rounded corners, or affect the electrical characteristics of the circuit.
When double wiring, on both sides of wire should be vertical to each other, oblique or bend the wiring, avoid parallel to each other, in order to reduce parasitic coupling.
PCB use 45 ° line as far as possible, instead of 90 ° line wiring, as to reduce the emission of high frequency signal foreign and coupling.
As input and output of the circuit with printed adjacent parallel wires should avoid as far as possible, lest produce reflux, best between the conductor and ground wire.
When the panel wiring density difference is larger, should with mesh copper foil filling, grid size 02 mm (8 mil)
Patch welding plate can’t put a hole, in order to avoid lost welding paste components virtual welding.
Through the socket between important signal lines are not allowed to.
Lie with resistor, inductor (plug-in), electrolytic capacitors and other components below step to avoid a hole, hole after welding and to avoid the peak components shell short circuit.
When the manual wiring, the power cord, first in the ground, and the power cord should be in the same level as far as possible.
Loop line cannot appear loopback wiring, if has to offer, try to let the small loop.
Wiring through between the two welding plate and not connected with them, they should keep the quantity big and equal spacing.
Wiring and the distance between the wires should be uniform, equal and keep maximum.
Wire and the solder joint of excessive smoothly, to avoid the small Angle.
When the center distance between welding plate less than the diameter of a solder, solder wire connection of the width may be the same and the diameter of the welding plate; When the center distance between the welding plate is greater than bonding pad diameter, should reduce the width of the wire; When there are more than three welding on a conductor plate, the distance between them should be greater than the width of the two diameter.
Printed wiring public ground should as far as possible arrangement at the edge of the PCB parts. Should retain as much as possible on the copper foil in PCB ground, so that the shielding effect is better than a strip of ground, transmission characteristic and the shielding effect will be improved, also have played an important role in reducing distributed capacitance. Printed wiring public ground best form a loop or mesh, this is because when there are many integrated circuits on the same piece of PCB, as a result of the limitation of graphics on the ground potential difference, leading to lower noise tolerance, as into a circuit, grounding potential difference.
The basic rule of wiring
The stand or fall of PCB design had a great influence on its anti-jamming ability. In PCB design, therefore, must observe the basic principles of design, and shall meet the requirements of the anti-interference design makes the circuit to obtain the best performance. In PCB design, wiring is an important step to complete the product design, can say in front of the preparation work for it.
In the PCB design, the design of the wiring process limit the highest, the finest, workload is the largest. PCB wiring is divided into single wiring, double-sided wiring and multilayer wiring 3 kinds. PCB wiring can use the system to provide the wiring two methods of manual and automatic wiring. Although system provides designers with a convenient operation, high completion rates of automatic wiring, but in actual design, there are still unreasonable place, this is where the designer manually adjust the PCB wiring, in order to obtain the best design effect.