[Altium Designer] PCB knowledge - copper pouring skills and settings

What are the pcb copper cladding skills? What is the pcb copper cladding setting method? The main function of pcb copper cladding is "reflow and shielding". The pcb copper cladding is mostly carried out in the grid method. The thickness of double-sided pcb copper cladding is about 35um (1.4mil); 50um is uncommon; the surface layer of the pcb copper clad multilayer board is 35um (1.4mil), and the inner layer is 17.5um (0.7mil). The thickness of pcb copper cladding is also expressed in OZ (ounces). The benefits of pcb copper cladding are "improving power efficiency, reducing high-frequency interference, and improving aesthetics". After talking about so much knowledge of pcb copper cladding, then pcb copper cladding skills and settings? We will now introduce the system "PCB copper cladding skills and settings?".

First, pcb copper cladding skills:

1. If there are many grounds on the PCB, such as SGND, AGND, GND, etc., according to the different positions of the PCB surface, the most important "ground" is used as the reference to independently cover copper, digital ground and analog ground. There is not much to say about copper plating separately. At the same time, before copper plating, first thicken the corresponding power supply lines: 5.0V, 3.3V, etc. In this way, multiple deformable structures of different shapes are formed.

2. For single-point connection of different grounds, the method is to connect through 0 ohm resistance or magnetic beads or inductance;

3. Copper cladding near the crystal oscillator. The crystal oscillator in the circuit is a high-frequency emission source. The method is to apply copper around the crystal oscillator, and then ground the shell of the crystal oscillator separately.

4. The island (dead zone) problem, if you think it is too big, then it will not cost much to define a ground via and add it.

5. At the beginning of wiring, the ground wire should be treated equally, and the ground wire should be routed well when routing. You cannot rely on the addition of vias after copper coating to eliminate the ground pin for connection. This effect is very bad.

6. It is best not to have sharp corners on the board (<=180 degrees), because from the electromagnetic point of view, this constitutes a transmitting antenna! For others that will always have an effect just big or small, I recommend using the edge of the arc.

7. Do not apply copper in the open area of ​​wiring in the middle layer of the multi-layer board. Because it's hard for you to make this copper "good ground"

8. Metals inside the equipment, such as metal radiators, metal reinforcement bars, etc., must be "well grounded".

9. The heat dissipation metal block of the three-terminal voltage stabilizer must be well grounded. The ground isolation belt near the crystal oscillator must be well grounded. In short: if the grounding problem of the copper on the PCB is dealt with, it will definitely be "pros outweigh the cons". It can reduce the return area of ​​the signal line and reduce the electromagnetic interference of the signal to the outside.

Second, the pcb copper cladding settings:

1. Safe spacing setting of pcb copper cladding:

The clearance of copper cladding is generally twice the clearance of wiring. However, before there is no copper cladding, the safe distance of the wiring is set for the wiring, then in the subsequent copper cladding process, the safe distance of the copper cladding will also default to the safe distance of the wiring. This is not the same as the expected result.

A stupid way is to double the safety distance after laying the wire, and then pour copper, and then change the safety distance back to the safe distance of the wiring after the copper pouring is completed, so that the DRC inspection will not report an error. This method is possible, but if you want to change the copper cladding, you have to repeat the above steps, which is a little troublesome. The best way is to set the rules for the safety distance of the copper cladding separately.

Another way is to add rules. In the Clearance of Rule, create a new rule Clearance1 (the name can be customized), then select Advanced(Query) in the WheretheFirstObjectmatches option box, click QueryBuilder, and then the BuildingQueryfromBoard dialog box appears, in the first line of the dialog box in the drop-down menu Select the default item ShowAllLevels, select ObjectKindis in the drop-down menu under ConditionType/Operator, and select Ploy in the drop-down menu under ConditionValue on the right, so that IsPolygon will be displayed in QueryPreview, click OK to confirm, the next step is not finished, completely saved An error will be prompted:

Next, just change IsPolygon to InPolygon in the FullQuery display box, and finally modify the copper-clad safety distance you need in Constraints. Some people say that the priority of wiring rules is higher than that of copper cladding. Copper cladding must also comply with the rules of safe spacing of wiring. It is necessary to add the exception of copper cladding to the rules of safe spacing of wiring. The specific method is in FullQuery Inside the annotation is notInPolygon. In fact, it is not necessary to do so, because the priority can be changed. There is an option priorities in the lower left corner of the main page of setting rules, which increases the priority of the safe spacing rule of copper cladding to higher than the safe spacing rule of wiring. Don't interfere, it's over.

2, pcb copper cladding line width setting:

When choosing between Hatched and None, you will notice that there is a place to set TrackWidth. If you choose the default 8mil, and the minimum line width is greater than 8mil when you set the line width range of the network connected to the copper coating, then an error will be reported in the DRC, and it was not noticed at the beginning. Details, DRC has a lot of errors after each copper pour.

In the Clearance of Rule, create a new rule Clearance1 (the name can be customized), then select ADVANCED(Query) in the WheretheFirstObjectmatches option box, click QueryBuilder, and then the BuildingQueryfromBoard dialog box appears, in this dialog box, the first line of the drop-down menu Select ShowAllLevels (the default is this), then select ObjectKindis in the drop-down menu under ConditionType/Operator, and then select Ploy in the drop-down menu under ConditionVALUE on the right, so that IsPolygon will be displayed in the QueryPreview on the right, click OK to confirm Save and exit, the next step is not finished, change IsPolygon to InPolygon in the FullQuery display box (bugs in DXP must be changed in this way, the 2004 version does not seem to need to be changed), the last step, you can modify what you need in Constraints below The spacing is up (according to your platemaking craftsmanship). In this way, only the spacing of copper laying is affected, and the spacing of each layer of wiring is not affected.


Which one is better, large-area copper coating or grid copper coating technology for PCB copper coating?

1. People often ask whether large-area copper coating is better or grid copper coating is better, and it is not good to generalize. why? The large-area copper coating has the dual functions of increasing the current and shielding, but the large-area copper coating may cause the board to warp or even bubble if it is subjected to wave soldering. Therefore, when copper is applied to a large area, several grooves are generally opened to alleviate the blistering of the copper foil.

2. The simple grid copper coating is mainly used for shielding, and the effect of increasing the current is reduced. From the perspective of heat dissipation, the grid is good (it reduces the heating surface of copper) and plays a certain role in electromagnetic shielding. . But it should be pointed out that the grid is composed of traces in staggered directions. We know that for the circuit, the width of the traces has its corresponding "electrical length" for the operating frequency of the circuit board (the actual size divided by The digital frequency corresponding to the operating frequency can be obtained, see related books for details). When the operating frequency is not very high, the effect of grid lines may not be very obvious. Once the electrical length matches the operating frequency, it will be very bad. You You will find that the circuit is not working properly at all, and signals are being emitted everywhere that interfere with the operation of the system. So for colleagues who use grids, my suggestion is to choose according to the working conditions of the designed circuit board, and don't hold on to one thing. Therefore, multi-purpose grids with high anti-interference requirements for high-frequency circuits, and circuits with large currents in low-frequency circuits are commonly used with complete copper plating.

PCB copper cladding and wire or via spacing settings?

       Menu bar-design-rules-electrical-clearance-select the right-click-new rule-left-click on the new rule-the setting box appears on the right-beside the advanced under the "wherethefirstobjectmatches" box above, click "ask builder"-left Select "objectkinds" in the drop-down box that appears in the condition type point, select "poly" in the "condition value" on the right - OK - "Ispolygon" appears on the right side of the setting box, change it to "Inpolygon", that is, the second letter S is changed to N - choose the smallest interval in the bottom constraint! 作者:机器喵与控制汪 https://www.bilibili.com/read/cv7083789/?ivk_sa=1024320u 出处:bilibili