Drawing of 4-layer PCB based on alicloud designer

4-layer PCB design (based on AD)

  Reprinted from:Http://blog.sina.com.cn/s/blog_982d7fa301019f21.html

tag: miscellaneous

category: technical _ hardware

Among the many operating layers provided by the system, there are two layers of electrical layers, namely the signal layer and the inner layer. These two layers have completely different properties and usage methods.

 

The signal layer is called the front-slice layer and is generally used for pure line design, including the outer line and the inner line. The inner electrical layer is called the negative layer, that is, the area without wiring or any component is completely covered by copper film, while the copper film is laid out in the place where wiring or the component is placed.

 

AddLayerIs to add a signal layer.
AddPlaneIs to add power layers, Layers

 

Analysis of Different stack Solutions
Solution 1

This scheme is the main selection layer setting scheme for the current 4-layer PCB in the industry. There is a ground plane under the component plane, and the top layer of key signals is preferred.

Top -----------------------

Gnd -----------------------

Power-----------------------

Bottom -----------------------

Solution 2

 

Gnd -----------------------

S1  -----------------------

S2  -----------------------

Power-----------------------

To achieve the desired shielding effect, this solution has at least the following defects:
A. the power supply and the ground are too far apart, and the power supply plane impedance is large.
B. the power supply and ground plane are extremely incomplete due to the influence of component pad.
C. Signal impedance discontinuous due to incomplete reference surface
In the current situation where a large number of table-mounted devices are used and the devices are increasingly dense, the power supply and ground of this solution are almost impossible to serve as a complete reference plane, and the expected shielding effect is very difficult to achieve; solution 2 has limited application scope. However, solution 2 is the best layer setting solution for individual Boards.

Solution 3

Similar to solution 1, this solution is applicable to scenarios where the main device is located in the bottom layout or the underlying cabling of key signals. This solution is generally restricted.

 

Top -----------------------

Gnd -----------------------

Power-----------------------

Bottom -----------------------

Conclusion: Select solution 1 and available solution 3.

 

for high-density PCB designed, it has been felt that the connection hole is not very suitable, wasting a lot of valuable wiring channels. To solve this contradiction, the blind hole and buried hole technology emerged. It not only achieves the effect of the guide hole, but also saves many wiring channels, make the cabling process more convenient, smooth, and complete. In most tutorials, blind holes and buried holes are also recommended in the design of multilayer circuit boards. Although this can make cabling easier, it also adds PCB design cost. Therefore, whether to choose this technology depends on the actual complexity of the circuit and economic capacity. This technology is not necessarily used in the process of designing a four-layer board based on the cost. If you think that the number of holes is too large, you can limit the upper limit of holes in the wiring rules before wiring.

 

Before wiring, horizontal wiring is used for the top layer in advance in the wiring rules, while vertical wiring is used for the bottom layer. In this way, the top layer and the bottom layer wiring are perpendicular to each other to avoid parasitic coupling.

Avoid using right angles or acute angles as they affect electrical performance in high-frequency circuits.

 

 

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How to draw 4-layer PCB

Reprinted from: http://www.eetrend.com/forum/100030744

 

Q:

How do ad experts draw 4 layers?

The main problems are:

1. Set the inner electrical layer;

2. Safe distance between the inner electrical layer;

3. Set VCC, Gnd, and + 5 V networks to the inner electrical layer.

I used to draw many pictures with 99se. Now I have a new version. So I want to learn how to use the new version. Please help me.

 

A:

Add layer is to add a signal layer.
Add plane is used to add power layers and layers.
The plane layer cannot be laid. It can only be copper coated and can be separated.

 

 

Among the many operating layers provided by the system, there are two layers of electrical layers, namely the signal layer and the inner layer. These two layers have completely different properties and usage methods.

The signal layer is called the front-slice layer and is generally used for pure line design, including the outer line and the inner line. The inner electrical layer is called the negative layer, that is, the area without wiring or any component is completely covered by copper film, while the copper film is laid out in the place where wiring or the component is placed.

In the design of multi-layer plates, the formation and power supply layer usually use the whole copper block as the line (or as a few large segments). If the middle layer is used) that is to say, if the opening layer is used, copper must be used for implementation. This will make the design data volume very large, which is not conducive to data exchange and transmission, and will also affect the design refresh speed, when using the inner electrical layer, you only need to set the connection mode with the outer layer in the corresponding design rules, which is very conducive to the design efficiency and data transmission.

 

The alicloud designer 7.0 system supports up to 16 layers of inner electrical layers and provides comprehensive control over inner electrical layer connections and DRC verification. A network can specify multiple inner electrical layers, and an inner electrical layer can be divided into multiple regions to set multiple different networks.

1 inner electrical layer

In PCB design, adding and editing the Interior Point layer is also done through the layer stack manager. The following describes how to operate the inner electrical layer based on an actual design case. Ask the reader to create a PCB design file or open a ready-made PCB design file.

In the PCB Editor, run the [design] | [layer stack manager] command to open the [layer stack manager ].

Click Select signal layer. The newly added inner layer is located below it. Select the signal layer and click Add layer. A new inner layer is added to the bottom of the selected signal layer.

Double-click the new inner layer to enter the edit layer dialog box. You can set its properties, as shown in 7-13. In the dialog box, you can set the name, thickness, network, and obstacle width of the inner electrical layer. The obstacle "pullback" is a closed copper removal Boundary set at the edge of the inner electrical layer to ensure a safe gap between the inner electrical layer boundary and the PCB boundary, the boundary of the inner electrical layer will be automatically rolled back from the boundary of the plate body.

Run design | board layers & colors ...] Command. On the "board layers & colors" tab, check the "show" check box after the "Ground" of the added inner electrical layer, as shown in 7-14, so that it can be displayed in the PCB work window.

For more information, see the appendix 《

alicloud designer inner and inner layers

http://www.eetrend.com/files-eetrend/altium_designer_nei_dian_ceng_yu_nei_dian_ceng_fen_ge_.pdf