Summary of the production method of Allegro component packaging (PAD)

In the allegro system, the pin of a part must be created before a symbol is created ). There are two types of component encapsulation: Table Pasting and direct insertion. For different packages, you need to create different padstacks.

The padstack in Allegro mainly includes the following parts:. 1. There are three types of pad: Physical pad for components:

1. Regular pad, rule pad (in main ). It can be circle, square, oblong, rectangle, Agon, and shape (which can be any shape ).
2. Thermal relief hot-air Solder Pad (either in the positive and negative parts ). It can be null (none), circle, square, oblong, rectangle, Agon, and Flash (any shape ).
3. Anti-padding (used in negative parts), used to prevent the pin from connecting to other networks. Optional values: NULL (none), circle, square, oblong, rectangle, Agon, and shape (any shape ).

2. soldermask: solder mask, so that the copper foil is exposed and can be coated. 3. pastemask: adhesive tape or steel mesh. 4. filmmask: Reserved Layer, which is used to add the information you need to add. It can be used as needed.

The layer and size to be set for the encapsulated pad of the table sticker Element: Regular pad: the actual package size is adjusted accordingly. We recommend that you use the recommended sizes in IPC-SM-782A surface mount design and Land Pattern standard for dimensional design. It is also recommended to use IPC-7351A LP viewer. This software includes the encapsulation of most commonly used SMD components. The dimension and pad design dimensions are provided. You can download it from www.pcblibraries.com for free.
Thermal relief: generally 20 mil larger than regular pad. If the size of regular pad is smaller than 40 mil, reduce it as needed.
Anti pad: generally 20 mil larger than regular pad. If regular pad is smaller than 40 mil, reduce it as needed.
Soldermask: generally 4mil larger than regular pad.
Pastemask: generally 4mil larger than regular pad. Filmmask: it seems that it is rarely used. It is the same diameter as soldermask for the moment.

Layers and dimensions to be set for the encapsulated Solder Pad of the direct plug-in element: Required level:

• Regular pad
• Thermal relief
• Anti pad
• Soldermask
• Pastemask
• Filmmask

1) Begin layer ----- thermal relief pad and anti pad are 0.5 larger than the actual pad 2) end Layer and begin Layer 2) default internal size is as follows: drill_size> = physical_pin_size + 10mil regular pad> = drill_size + 16mil (drill_size <50) (0.4 1.27) Regular pad> = drill_size + 30mil (drill_size> = 50) (0.76 1.27) Regular pad> = drill_size + 40mil (when drilling is rectangular or elliptical) (1mm) thermal pad = traxbxc-d Where traxbxc-D is the name of Flash (which will be introduced later) anti pad = dril L_size + 30mil 0.76mm soldermask = regular_pad + 6mil 0.15mm pastemask = regular pad (optional) • flash name: traxbxc-D wherein:. inner diameter: Drill size + 16mil B. outer diameter: Drill size + 30mil C. wed open: 12 (when drill_size = 10mil or lower) 15 (when drill_size = 11 ~ 40mil) 20 (when drill_size = 41 ~ 70mil) 30 (when drill_size = 71 ~ 170 mil) 40 (when drill_size = 171 mil or above) also has this statement: As for the Open Width of flash, it is necessary to calculate according to the circumference rate to ensure that the connection width is not less than 10mil. Formula: Drill size × sin30 ° cosine sine function 30 degree cosine ﹚Comment [B. K.1]: Isn't that 1/2? To be discussedD. angle: 45 Figure 1 through hole pad (the thermal relief in the figure uses flash)Required class/subclass for PCB components (Symbol)* These layers have been added when pad is added. Other layers must be added when an encapsulation is created in Allegro. ** For place_bound_top, the dip element is 1mm SMD larger than the part frame. Note: These layers can be excluded from other layers except marked as necessary. Other layers can be added as needed.

 

 

 

Serial number	Class	Subclass	Element	Remarks
1 *	ETH	Top	PAD/pin (via hole or table sticker) shape (cooling copper foil under SMD ic)	Required and conductive
2 *	ETH	Bottom	PAD/pin (through hole or blind hole)	Depends on your needs and is conductive
3 *	Package Geometry	Pin_number	Maps the pin number of the schematic element. If pad is not labeled, it means the schematic does not care about the pin or the mechanical hole.	Required
4	Ref des	Silkscreen_top	The position number of the component.	Required
5	Component Value	Silkscreen_top	Component Model or value.	Required
6	Package Geometry	Silkscreen_top	Component shape and Description: line, arc, word, shape, etc.	Required
7	Package Geometry	Place_bound_top **	The component occupies an area and height.	Required
8	Route keepout	Top	Wiring prohibited area	Depends on your needs
9	Via keepout	Top	Hole removal prohibited	Depends on your needs

 

 

Remarks:1. Concepts and usage of regular pad, thermal relief, and Anti padA: Regular pad (regular pad) is mainly used to connect to all headers such as top layer, bottom layer, and internal layer (including wiring and copper-clad ). Generally, it is applied to the top layer, bottom layer, and signal layer, because these layers are mostly used as main slices. Thermal relief and anti pad are mainly used to connect and isolate the negative slice. Generally, it is applied to VCC, Gnd, and other inner electrical layers, because these layers are mostly used as negative films. However, in the begin layer and end layer, we also set the thermal Relief (hot-press pad) and anti Pad Parameters, because the begin layer and end layer may also be used as the inner electrical layer, it may also be a negative slice. To sum up, that is to say, for a fixed pad connection, if this layer is the main pad, it is connected to the pad through the regular pad you set, thermal Relief (hot-air pad ), the anti pad (isolation disk) has no effect on this layer. If this layer is negative, it is connected and isolated through thermal Relief (hot press pad) and anti pad (isolation tray). Regular pad has no effect on this layer. Of course, a pad can also be connected to the top layer using the regular pad. At the same time, thermal Relief (hot-air pad) can be connected to the negative parts of the Gnd inner layer through the network.

2. Concepts of positive and negative partsA: The positive and negative slices only show different effects on one layer. Whether you set the front or back slice on this layer, the PCB is the same. In the process of cadence processing, data volume, DRC detection, and software processing are different. It is just two ways of expressing a thing. As mentioned in a brother's post, the video is what you see, what you see, and wiring. The negative slice is nothing you see. What you see is exactly the copper that needs to be corroded.

3. How should we use and set up the three pad types (regular pad, thermal relief, and Anti pad) during opening and loading?A: When we make a pad, we 'd better set all three parameters in flash. Whether you make a positive or negative tablet, it will always be done once and for all. If you don't need a negative slice, congratulations, you can say goodbye to flash. If you do not need flat pad on the inner layer when creating a pad, the flat pad will not appear if the power supply layer is a negative pad on the multilayer Panel. It will only be available if it is done in the early stage. if you do not want to pad the pad When plotting, you can directly remove the pad in the art work negative. Of course, you can also use the direct copper paving method for the main plate on the power layer, and set parameters such as the connection mode of the hole during the hole laying, which can also achieve the effect of the flower pad, in this way, when the pad is made, you can set the hole connection mode to achieve the effect of the pad. Set the parameters in shape-Global Dynamic Parameter-thermal relief connects. Each pin can have all types of pad (regular, thermal relief, anti-pad and custom shapes), which will be applied to various cabling layers in the design. For the negative parts in the artwork layer, Allegro uses thermal relief and anti-pad. For the video, Allegro only uses regular pad. These tasks are automatically selected by Allegro when generating the optical file. In each layer, regular thermal relief and anti-pad may be specified for the following reasons: When a drawing file is connected to the pad in this layer, the normal cabling occurs, in the main chip cabling layer, Allegro will decide to use the regular pad. If it is copper pad, use thermal relief pad. If it cannot be connected, use anti-pad. The specific use is determined by Allegro.

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Summary of the production method of Allegro component packaging (PAD)