Double Layer PCB board to use the two sides of the wire, must be between the two sides have the appropriate circuit connection Caixing. The "bridge" between such circuits is called a guide hole. The guide hole is in the pcb, filled with or coated with metal holes, it can be connected with the two sides of the wire. Use PROTEL to draw double-sided pcb board, in TopLayer (top layer) to draw wire connection components, is in the top drawing board; select BottomLayer (bottom), in the bottom of the wire to connect components, is the bottom of the drawing board. Above is the basis for painting Double Layer PCB.
In the painting Double Layer PCB board before the first to determine the layout of components, and when the first cloth in the first line of crystal, crystal circuit, clock circuit, CPU and other signal lines, must comply with the principle of small circulation area as small as possible.
Double board in the rational layout of the components to determine, followed by the first design to copy the power cord, and then cloth important line --- sensitive lines, high-frequency line, after the cloth line --- low-frequency line. The key leads are preferably a separate power supply, ground circuit, lead and very short, so sometimes the edge of the line with a line close to the signal line, let it form the smallest working loop.
In the painting Double Layer PCB board, in accordance with the "first big after the small, first difficult after the" layout principle, that is important unit circuit, the core components should be preferred layout, layout should refer to the block diagram, according to the main board Signal flow to the main arrangement of the main components.
The high-frequency signal is separated from the low-frequency signal; the interval between the high-frequency components and the low-frequency signal is separated from the digital signal; the high-frequency signal is separated from the low-voltage signal; To be full.
It should be noted that the two double-layer board in the lower part of the circuit board has a ground plane. This is designed so that engineers can quickly see wiring when doing troubleshooting, often in the device manufacturer's demonstration and evaluation board. But the more typical approach is to lay the ground plane on the top of the board to reduce the electromagnetic interference (emi).
Draw Double Layer PCB board steps:
1, prepare the circuit schematic
2, create a new pcb file and load the component package library
3, planning circuit board
4, into the network table and components
5, automatic component layout
6, layout adjustment
7, network density analysis
8, wiring rules set
9, automatic routing
10, manually adjust the wiring