Copying Printed Circuit Board Layout Scheme according to the circuit board data colleted through reverse engineering, the specific operations are as follows:
(1) Open the reverse engineering pcb board software, the reverse engineering circuit board software used in this example is Quick-Pcb (multilayer board can be copied, the line width is greater than 0mil), click on the file \ open the base map \ select the file
(2) According to the printed circuit board data provided by reverse engineering skill, operate on the top of Figure 3-d in the order of pads, vias, wires, and copper surfaces. When adding objects, the position accuracy of the pads and vias should be sufficient Guarantee, there may be some errors in the accuracy of the wire and copper surface, so we have to check the scanned image see below picture.
Copying Printed Circuit Board Layout Scheme
When connecting the wires, you need to follow the PCB layout design rules of the wires, especially the routing mode of the corners of the wires. Generally, 45 degrees is preferred, followed by the arc and the right angle.
When draw pcb shematic layout, it is generally necessary to avoid the conductors running at right angles. In principle, the right-angle wiring will cause the line width of the signal line to change, resulting in impedance discontinuity. The impact of right-angle wiring on the signal is:
One is that the right-angle corner trace is equivalent to the capacitive load of the signal line, which will lead to slow down the rise time;
The second is due to the discontinuity of the impedance, resulting in signal reflection; the third is that the tip of the right corner should be concentrated force, easy to crack, and EMI will also be generated.
