Illustrated tutorial on P-CAD. Manually creating a footprint Pad stack

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Printed circuit boards contain simple (Simple) And complex (Complex) stacks contact pads and vias (Via Stacks). A pad stack is a file that contains a description of the pad graphics in the various PCB layers and the photoplotter aperture number.

Rice. 2.15. Project technological parameters window

Stacks for pin terminals (DIP-cases) of components that have the same shape of contact pads on all layers of the PCB, and stacks for components with planar leads (SMD-cases), having contact pads on one layer of PP, form simple stacks. Planar pin components are placed on layers Top or Bottom(the graphics of the housings of these components are also set on the same layers). Complex Stacks on different layers of PP can have different geometric shapes. Stack first contact component must be different (for example, square) from other stacks of the same component.

To form (edit) stacks command is executed Options/Pad Style(Fig. 2.16). In area Current Style at the beginning of operation there is usually only one pad stack - Default. highlight the line Default, press the button Copy and in the window Pad Name enter the name of the new pad stack (for example, dip17) and press OK. In area Current Style The name of the new pad appears. Similarly, you can sequentially enter the names (names for now!) of all the necessary stacks.

In Fig. Figure 2.16 shows examples of stacks, the names of which reflect the shape and size of the pads:

Rice. 2.16. Pad stacks

dip17- round platform with a diameter of 1.7 mm;
DIP12- round platform with a diameter of 1.2 mm;
plan2108- planar platform measuring 2.1 x 0.8 mm;
REC1212- square (rectangular) area measuring 1.2 x 1.2 mm.

2.4.1. Pad Stacks and Via Stacks

The data in the current paragraph is generated for the subsequent “shoeing” of the component pins. Pads for component pins and vias can be various shapes and sizes. Therefore, for the element base used in development, the user creates his own libraries pad stacks And vias, which are stored in project technological parameters file Design Technology Parameters(extension .dtp).

This file contains information about other project parameters - the values of permissible gaps, the structure of layers, properties and classes of individual circuits, etc.

To create a technological parameters file in the editor P-CAD Pattern Editor do the following:

run the command Pattern/Design Technology Parameters, out the window File name enter a file name (for example Murgo), click the button Open, and then confirm the opening of a new (currently empty) process parameters file;
uncheck the box Read-only file click the button New Group and enter your project name and click OK;
select the project name and to create sections of the technological parameters file, click the New button Section(type of edited parameter group). The window shown in Fig. 2.14. Check the boxes Pad Styles and Via Styles and press OK;

Rice. 2.14. Window Design Technology Parameters...

highlight the line Pad Styles, click the button New Item(new pad type), enter the name of the pad to be created (the name you enter should reflect some parameters of the stack being created, for example the name smd2108 shows that the platform is planar in size 2.1mm X 0.8 mm, and the name dip17 means that the platform is through and its outer diameter is equal to 1,7 mm) and press OK;
repeat the operation of naming the pads as many times as there are types of pads in your project (pads can be deleted or renamed if necessary). Note that the geometric shapes and dimensions of the contact pads for holes in the PCB are determined by the design and technological documentation in force at the enterprise.

The view of the window after carrying out these operations is shown in Fig. 2.15.

When the checkbox is enabled Read-only file window Design Technology Parameters data cannot be edited.

Printed circuit boards contain simple (Simple) And complex (Complex,) stacks contact pads and vias (Via Stacks). Stack of pin sites - This is a file that contains a description of the pad graphics in the various PCB layers and the photoplotter aperture number.

Rice. 2.15. Project technological parameters window

Stacks for pin terminals (DIP packages) of components that have the same pad shape on all PCB layers, and stacks for components with planar leads (SMD packages) having contact pads on one layer of PCB form simple stacks. Planar pin components are placed on layers Thor or Bottom(the graphics of the housings of these components are also set on the same layers). Complex Stacks on different layers of PP can have different geometric shapes. Stack first contact component must be different (for example, square) from other stacks of the same component.

For formation (editing) of stacks command is executed Options/Pad Style(Fig. 2.16). In area Current Style at the beginning of operation there is usually only one pad stack - Default. highlight the line Default click the button Sora and in the window Pad Name enter the name of the new pad stack (for example, dip17) and click OK. In area Current Style The name of the new pad appears. Similarly, you can sequentially enter the names (names for now!) of all the necessary stacks.

In Fig. Figure 2.16 shows examples of stacks, the names of which reflect the shape and size of the pads:

Rice. 2.16. Pad stacks

dip17- round platform with a diameter of 1.7 mm;
DIP12- round platform with a diameter of 1.2 mm;
plan2108- planar platform measuring 2.1 x 0.8 mm;
REC1212- square (rectangular) area measuring 1.2 x 1.2 mm.

After highlighting the stack name and clicking the button Modify (Simple) open the menu for editing simple pad stacks (Fig. 2.17).

Rice. 2.17. Window for editing simple stacks

In area Toure select the type of contact pad:

Thru- contact pad for pin output;
Torus - contact pad for planar output from the side where the component is installed on the PCB;
Bottom- contact pad for planar output on the component mounting side.

In area Plane Connection the type of contact pads is indicated when connecting them to continuous metallization layers:

Thermal- contact pad with a thermal barrier;
Direct- solid contact pad, directly connected to the metallization layer.

In the window list Shape The shape of the contact pad is set:

Ellipse- elliptical (circle);
Oval- oval;
Rectangle- rectangular;
Rounded Rectangle- rectangular with rounded corners;
Target- crosshair for drilling;
Mounting Hole- mounting (mounting) hole.

The table shows the internal (d) diameters of the holes and diameters (D) of the contact pads for PCBs of the 4th accuracy class.

Table. Diameters (mm)


D	0,6	0,8	1,0	1,2	1,5	1,8
D	1,0	1,15	1,4	1,65	2,0	2,3

The geometric dimensions of the contact pads are set in the windows Widht(width), Height(height) and Diameter(diameter of hole for drilling). If the hole is metallized, then in the area Hole checkbox is checked Plated.

In area Plane Swell value is set gap between the metallization layer and contact pads and vias not connected to it. This gap is maintained during automatic routing of connections on the printed circuit board. After all settings, click OK.

With discharge the desired name stack and button press Modify (Complex) in the dialog box Options Pad Style (Complex) editing is in progress complex pad stacks(Fig. 2.18).

In the window Layers sequentially indicate the names of the layers on which the stack pads will be placed. Layer names appear when the list of layers is expanded in the window Layer region Pad Definition, the desired layer is selected from the list and added to the field

Layers when you click on Add button. In the windows Shape, Width and Height region Pad Definition indicate the shape of the pad on the selected layer, its width and height, respectively.

Rice. 2.18. Editing complex stacks

On the list Shape Thirteen options for contact pad shapes are indicated:

Polygon- contact area defined by the polygon;
Thermal 2 Spoke- contact pad with two thermal barriers;
Thermal 2 Spoke/90- contact pad With two thermal barriers rotated 90°;
Thermal 4 Spoke- contact pad with four thermal barriers;
Thermal 4 Spoke/45- contact pad with four thermal barriers rotated by 45°;
Direct Connect- contact pad with direct connection to a continuous metallization layer.
Other options - as for contact pads with simple forms.

When selecting a pad in the form thermal barrier in the appearing windows Outer Dia/Inner Dia The values of the external and internal diameters of the site are entered. In the window Spoke Width the width of the thermal barrier is set.

In area Hole in the window Diameter the diameter of metallized/non-metallized is set (the checkbox is turned on/off Plated) hole connecting the PP layers. Displacement of the center of the hole relative to the center of the photocoordinate aperture (horizontally - X Offset and vertically - Y Offset) determined by the equipment used to make photomasks.

After finishing setting the parameters for each contact pad button pressed Modify.

After completing the data settings for the stack across all layers click OK, and in the window that appears Options Pad Style(Fig. 2.16) to view stack sections (only for through holes!) pads in all layers of the printed circuit board, a button is pressed Modify Hole Range(Fig. 2.19).

Figure 2.19. Cross section of pad stacks

Then in the area Styles select the name of the stack and view images of its sections across all previously installed layers of the printed circuit board.

Via Stacks are formed after the command is executed Options/Via Style similar to the formation of pad stacks.

Project via stack names are set by command Pattern/Design Technology Parameters(see Fig. 2.15).

All generated stacks of pads can be placed on the working field of the PCB after executing the command Place/Pad programs P-CAD Pattern Editor. This placement of stack pads is carried out to form the installation location of the component for the purpose of subsequent recording it in the library or in separate file(extension PAT).

Setting up the PCB Editor

The PCB graphic editor is used to place components on a printed circuit board and manually trace them in P-CAD. This section discusses the preliminary configuration of the editor.

Launching the Printed Circuit Board (PCB) Editor

The P-CAD PCB Editor can be launched from the Windows Start menu or from the Schematic editor.

Launch the PCB Editor from the Schematic Editor

1) Activate the Utils/P-CAD PCB command in the circuit editor.

2) The package splash screen will appear, and then the working screen of the PCB editor (see Fig. 7−1).

Rice. 7−1. PCB Editor work screen

The PCB editor is built in the same way as the circuit editor - the only difference is in the objects it works with. Therefore, new buttons appeared on the toolbars, and new commands appeared on the menu.

PCB Editor Configuration

Setting up the configuration of the P-CAD PCB graphic editor is in many ways similar to setting up the Schematic graphic editor, described in detail in Section 3, so here we will pay attention only to the main points necessary for the work.

Setting General Project Options

Establish metric units and sufficient dimensions for work working area

1) Activate the Options/Configure… command in the main menu.

2) In the Options Configure panel, in the General tab, in the Units frame, select the mm check box to switch to the metric system of units.

3) In the Workspace Size frame, in the Width (width) and Height (height) windows, set the values shown in Fig. 7−2 (they must be larger than the dimensions of the designed printed circuit board).

Rice. 7−2. Setting General PCB Editor Options

The remaining parameters on this tab can be left unchanged. Their meaning is deciphered in table 7−1.

Setting process control parameters

When laying conductors, the system can monitor compliance with technological standards (gaps, conductor width, etc.)

Configure process control

1) Go to the Online DRC (interactive control) tab.

2) Check all the boxes as shown in Fig. 7−3.

Rice. 7−3.Setting parameters for checking technological limitations

Checking the Enable Online DRC checkbox allows you to perform on-the-fly checks while working with board elements. To enable the appropriate type of check, you must additionally select the checkboxes in the Report Options group (see Table 7-2).

Clicking the Design Rules... button allows you to set design rules for the entire project, each layer, individual net, net class, etc. Clicking the Severity Levels button allows you to set severity levels for individual errors. But more on that later (see section 10).

Setting manual and interactive tracing options

Global rules for manual and interactive routing for the entire project are set on the Route tab.

Set tracing options

1) Go to the Route tab.

2) Set the parameters and checkboxes on it as shown in Fig. 7−4.

Rice. 7−4. Setting Trace Options

Let's consider the purpose of these elements in more detail.

Selecting the T-Route Default checkbox enables the T-shaped conductor layout mode as the main one. In this case, the route branches can be in arbitrary places. It is recommended to enable this checkbox.

The Highlight While Routing group specifies the highlighting mode for the current net while routing. It is more convenient to work when not only the pads are highlighted (Pads Only checkbox), but also conductors and connections (Pads, Traces and Connections checkbox).

In the Miter Mode frame, the mode for smoothing kinks in conductors is set. Smoothing is possible using a line segment at an angle of 45 degrees (Line) or a circular arc (Arc).

The selection of keys to complete interactive circuit routing is made in the Manual Route frame. Checking the Right Mouse to Complete/Slash Key to Suspend checkbox allows you to use the right mouse button to automatically complete the route along the shortest path. The “/” (slash) key in this case is used to stop tracing. For those who are accustomed to the fact that when you press the right mouse button the current operation is terminated, the second checkbox Slash Key to Complete/ Right Mouse to Suspend would be preferable.

The Orthogonal Modes frame sets the methods for drawing wires and lines. Possible options are:

90/90 Line-Line drawing sections of lines and conductors at an angle of 90 degrees;

45/90 Line-Line – drawing lines and conductors at an angle of 90/45 degrees;

90/90 Arc-Line – pairing of conductors located at an angle of 90 degrees with an arc is performed;

Tangent Arc – arcs tangent to conductors with the current radius are created.

In the Interactive Route frame, parameters for interactive routing are set. The Stub length group specifies the minimum length of a line segment (in grid units) to establish a connection to a pad.

At installed utility InterRoute Gold has a number of other options available. Selecting the Maximize Hugging checkbox in the Trace Length group ensures that the new trace is pressed as closely as possible to the existing ones. The Minimize Length mode allows you to lay a route of minimum length with a minimum of vias (see paragraph 9.5.6).

When the Honor Layer Bias checkbox is checked, routes will be laid taking into account priority directions in individual layers.

Selecting the Show Routable Area checkbox makes the preferred routing areas visible. When working in Windows NT, 2000, the tracing area is shown as a transparent hatch, and in Windows 95/98 it is highlighted in color.

Setting production parameters

On the Manufacturing tab, you set the parameters used in the production of printed circuit boards (Fig. 7−5).

Rice. 7−5. Setting production limits

So the Solder Flow Direction group of checkboxes allows you to specify in which direction the solder flow crosses the board. Possible values: Top to Bottom, Left to Right, Right to Left and Bottom to Top. Selecting the Synchronize Components to solder flow, on OK checkbox allows you to automatically match the orientation of components to the selected direction of solder flow. The remaining parameters on this tab determine the size of the protective masks. Their purpose is given in table. 7−3.

View the Manufacturing tab and close the Options Configure panel, saving your settings.

Setting Layer Configuration

IN graphic editor PCB of the PCAD system, in contrast to the circuit editor, adopts a layer-by-layer (group) organization of image elements. For clarity, we can assume that each group of image elements (layers) is drawn on a transparent film, which are then assembled into a package, forming a solid image. On one layer, conductors are drawn on the top side of the printed circuit board, on the other - on the bottom, on the third - the boundaries of the printed circuit board, etc. A total of 99 layers are possible in the system. Some layers are system (mandatory), others can be added by the user. Setting the layer configuration is one of the most important operations. The system default configuration is for double-sided PCB. The name and purpose of the layers specified in the system by default are given in Table. 7−4.

View the current layer configuration

1) Activate the Option/Layers command in the menu.

2) The Option Layers panel will appear (see Fig. 7−6).

Rice. 7−6. Setting Layer Configuration

The Layers tab displays the current layer configuration and tools for adding and modifying layers.

The Current Layer combo box shows the name of the current layer, i.e. layer on which the work is performed.

The Type frame specifies the type of the new layer. There are three options:

Signal – signal wiring layer;

Plane – metallization layer for connecting power;

Non Signal – a layer that does not carry information about electrical circuits (case graphics, texts, dimensions, etc.).

In the Layers list, the layer type corresponds to the first letter in the second column.

Each layer can be turned on or off using the Enable and Disable buttons, respectively. The state of the layer is displayed by the second letter in the second column of the Layers window.

In the Routing Bias group, indicate the preferred orientation of printed conductors in the selected signal layer. IN middle column in the Layers window this parameter is displayed as the third letter. The following options are available: Auto – automatic selection of orientation; Horizontal – horizontal orientation; Vertical – vertical orientation.

Add a new layer

1) In the Layer Name window, type Appearance

2) In the Layer Number window, enter 12

3) In the Type frame, check the Non signal checkbox.

4) Click the Add button.

The name of the new layer appears in the list of layers.

On the Sets tab (groups), layers are combined into separate groups for highlighting, displaying or printing.

Add a new group

1) In the Set Name window, type Build

2) Click the New button. Name new group will appear in the Layer Sets window.

3) Press the CTRL key and, without releasing it, select with the left mouse button the set of layers shown in Fig. 7−7.

Rice. 7−7. Layer groups

4) Click the Add-> button. The names of the selected layers will appear in the Set Contents window.

Rice. 7−8. Drawings design tab

If the Document Toolbox utility is installed, another tab appears on the Option Layers panel - Titles (Fig. 7−8, which allows you to interactively edit the design of layer-by-layer drawings and the board assembly drawing. In meaning, this tab is reminiscent of the Option Sheet window of a graphics editor schematic diagrams Since printed circuit board drawings are produced, as a rule, on an enlarged scale, this tab, apparently, can only be used for drawing up assembly drawings.

Setting Grid Options

To facilitate work, all design elements of the PP on the working field are tied to the nodes of a special grid. Grid parameters (distance between nodes, grid type, grid type) are set using the Options/Grids... command. In this case, a special Options Grids panel appears, shown in Fig. 7−9. The meaning of the parameters set on this panel was discussed in detail in paragraphs. 3.3.

Rice. 7−9. Setting Grid Options

Set the required mesh steps

1) Activate the Option/Grids… command

2) By typing values in the Grid Spacing window, add them to the list in the Grids window using the Add button (see Fig. 7−9).

3) Remove unnecessary values from the list using the Delete button.

4) Check all the boxes as shown in Fig. 7−9 and click OK.

Setting display options

Using the Options/Display main menu command in the Options Display panel, you can set colors and display styles various objects scheme. The window of this command contains two tabs (see Fig. 7−10).

Rice. 7−10.Installation color palette PCB

View assigned colors and display options

1) Activate the Options/Display command

2) On the Options Display panel in the Colors tab (Fig. 7−10), change the colors for individual elements images, if necessary.

Here, in the Layer/Item Colors frame, the colors of vias (Via), pads (Pad), lines (Line), polygons (Poly) and texts located in separate layers are set.

In the Display Colors frame, you can set the colors of the background of the working field (Background), lines of logical connections between component pins (Connects), normal and large grids (1x Grid & 10x Grid), boundaries of trace prohibited areas (Keepout), highlighted elements ( Highlight), selected elements (Selection) and fixed components (Fixed).

The Defaults button in this tab allows you to restore the default color palette set in the system.

Go to the Miscellaneous tab to set additional panel display options.

Here (see Fig. 7−11) you can set the display modes of Glue Dots for surface-mount elements, pointers for automatic installation (Pick and Place) and violations of technological restrictions (DRC Errors). There are three display options for these elements: Show – show all; Hide – hide everything; No Change – be guided by setting the parameters of an individual element.

Rice. 7−11. Extra options display

For free pads (Free Pads group), it is possible to display pin indicators (Pin Des) or pad numbers (Number).

In the Cursor Style frame, you can set the type of cursor: Arrow, Small Cross, or Large Cross.

The meaning of the remaining parameters set on this panel in the Miscellaneous frame is revealed in the table. 7−5 (also see paragraph 3.6).

The Defaults button in this tab allows you to restore the default settings for the specified elements in the system.

After completing the settings, close the Options Display panel by clicking OK.

Setting up your keyboard and mouse

The Options/Preferences command allows you to customize your keyboard and mouse.

Review your keyboard and mouse settings

1) Activate the Options/Preferences command.

2) In the Options Preferences panel in the Keyboard tab, you can redefine the assignment of hot keys for frequently used commands (Fig. 7−12, a). Here you can assign a key or key combination to any command in the main menu if you select the Menu Command option in the Command Type group, or to created macros (Macros option). However, special shortcut commands (Shortcut commands option) specifically designed to make working on the board easier are more significant and useful.

3) On the Mouse tab (see Fig. 7−12, b) you can define the behavior of the CTRL and SHIFT keys. When the “Ctrl extends selection. Shift subselects” in the Ctrl/Shift Behavior group, pressing the CTRL key allows you to select multiple objects. Pressing the SHIFT key allows you to select subobjects (attributes) of components. Checking the “Ctrl subselects. Shift extends selection” changes the purpose of these keys.

Rice. 7−12. Options Preferences panel

4) Checking the Double-Click Displays Properties checkbox allows you to double-click the left mouse button to open the object’s properties window.

5) Checking the Allow Single Select on All Enabled Layers box makes them available for selection by left-clicking or right click mouse over objects on layers that are not current.

6) Close the Options Preferences panel.

Setting the current parameters of lines and conductors

Using the Options/Current Line command, a set of required thicknesses of lines and conductors is set.

Set the required line thicknesses

1) Activate the Options/Current Line command.

2) On the Options Current Line panel (Fig. 7−13, a) in the Line Width window, enter the required line width value.

3) Click the Add button. The new value will appear in the line list window.

4) Repeat paragraphs. 2−3 for all set line thicknesses (see Fig. 7−13, a).

Rice. 7−13. Setting line parameters, routing barriers, and smoothing radii

6) Click OK to complete the dialog.

Setting the current trace barriers settings

To prohibit the laying of conductors in certain areas of the printed circuit board, the P-CAD system uses so-called routing barriers. The Options/Current Keepout command (see Fig. 7−12, b) allows you to set the current drawing style of tracing barriers and their influence. In this case, tracing barriers can be displayed as a shaded area (Polygon) or as lines Line (see the figure on the right). The checkboxes in the Layers group allow you to extend the effect of the barrier only to the current layer (Current checkbox is selected) or to all signal layers (All checkbox).

Smoothing polygon corners

Using the Options/Current Radius command, the current parameters for smoothing the corners of polygons (polygons) and other elements performed as polygons are set. When this command is activated, the Options Current Radius panel appears (see Fig. 7−13, c), on which you can specify a list of allowable smoothing radii (in the Radius window) and set the degree of approximation of the smoothing polyline to the circular arc (in the Current Chord Height window - maximum distance of a chord from a circle). By default, the system has three values for smoothing radii: None – smoothing is not performed; Crid and Crid/2 – smoothing radius is equal to the current grid step or half of it.

Rice. 7−14. Options for smoothing polygon corners.

For example in Fig. 7−14 show the results of smoothing the corners of polygons entered as equilateral triangles. In Fig. 7−14, and the polygon without corner smoothing is shown (None is selected for the smoothing radius). In Fig. 7−14, b and 7−14, c show polygons with a smoothing radius Grid/2, but for the first the Current Chord Height value was set to 0.2 mm, and for the second - 0.01 mm. The red arrow in Fig. 7−14, c indicates the center of the smoothing arc.

Complete the list of acceptable smoothing radii

1) Activate the Options/Current Radius command.

2) On the Options Current Radius panel (Fig. 7−12, c) in the Radius window, enter the required radius value.

3) Click the Add button. The new value will appear in the list box.

4) Repeat paragraphs. 2−3 for all set radius values (see Fig. 7−12,c).

5) To remove an unnecessary element from the list, select it with the cursor and click the Delete button.

6) In the Current Chord Height window, set the required value for the maximum deviation between the ideal and actual arc.

7) Click OK to complete the dialog.

Setting text options

Setting text parameters is done using the Options/Text Style command and has no special features compared to setting text parameters in the schematic editor (see subsection 3.4).

Enter new text styles to print inscriptions in Russian on the board with font sizes of 3.5 mm, 5 mm and 7 mm

Creating Pad and Via Stacks

Pad and via graphics information in a P-CAD system can be stored separately from the package graphics. For this purpose, the Design Technology Parameters file with the .dtp extension is used. It is important to understand that for multilayer printed circuit boards, the shape and size of the contact pads in different layers may differ from each other. The P-CAD system introduced the concept of a set (stack) of contact pads - Pad Stack. The sets are united by the concept of a style that has a corresponding name. As a rule, in a new project, only one style is defined for pads - Default - the default style. This style cannot be deleted and its parameters cannot be changed.

To set a new style, use the Options/Pad Style command.

Pad stacks in the P-CAD system are divided into simple (Simple) and complex (Complex). For simple stacks, the shape and size of the pads are the same on all layers. For complex stacks, the shape and size of the pads on different layers will be different. Let's create three simple and one complex stacks.

Specifying Stack Names

Name the new pad stack styles

1) Activate the Options/Pad Style command.

2) On the Options Pad Style panel (see Fig. 7−15), click the Copy button to copy the style specified in the list to a new one.

Rice. 7−15. Options Pad Style panel.

3) In the Copy Pad Style panel that appears (Fig. 7−16), in the Pad Name window (stack name), type c110_p130_h090 and click OK.

Rice. 7−16. Specifying a name for the new style

4) Repeat paragraphs. 2−3, indicating new style names – s120_h080, c120_h080, Tr200x050

It is common practice to assign meaningful names to stacks to make them easier to select later. Classification may vary. IN in this case The following conventions are accepted: the shape of the contact pad and its dimensions are indicated (for complex stacks - by layer), and then the diameter of the mounting hole is indicated. Thus, the following pad stacks are defined:

s120_h080 – a simple stack with a square-shaped platform (the letter s in the name comes from the English word square) with a side size of 1.2 mm. The diameter of the mounting hole is 0.8 mm (the letter h in the name comes from the English word Hole - hole);

c120_h080 – simple stack with pad round shape(the letter c in the name is from the English word circle) with a diameter of 1.2 mm. Mounting hole diameter – 0.8 mm;

Tr200x050 – contact pad for planar output on the top side of the printed circuit board (Top), rectangle sized 2x0.5 mm

c110_p130_h090 – a complex stack with pads of different shapes - on the top side of the printed circuit board there is a round pad, on the bottom there is a polygon. The diameter of the mounting hole is 0.9 mm.

Setting Simple Stack Options

Since the default stack properties were copied, the real parameters of the pads do not correspond to their names.

Set simple stack parameters s120_h080

1) Specify the name of the style in the list (see Fig. 7−15).

2) Click the Modify (Simple) button

Rice. 7−17. Setting Simple Stack Options

3) In the Modify Pad Style (Simple) panel (Fig. 7−17), in the Shape list box, select the rectangular shape of the pad – Rectangle. The shapes of contact pads possible for simple stacks are listed in table. 7−6.

4) Set the height (height) and width (width) of the rectangle to 1.2 mm.

5) In the Type frame, select the value Thru - through hole. For planar pins, you need to select the top (Top) or bottom (Bottom) sides of the PCB

6) In the Diameter window of the Hole frame, set the diameter of the mounting hole to 0.8 mm and check the Plated checkbox, thereby indicating that the hole is plated.

7) In the Plane Connection frame, select Thermal mode with thermal barriers to connect to metallization layers. When the Direct flag is set, the pad is connected to the metallization layer directly without gaps.

8) In the Plane Swell frame, to set the gap between the metallization area and the contact pad, check the Use Global Swell checkbox to use the value specified in the Options/Configure project parameters. If necessary, you can set a local gap for a given stack in the Local swell window when the Use Global Swell flag is cleared.

9) Click OK to end the dialog.

Set the parameters for the stack yourself c120_h080

Note. For the shape of the contact pad, select an ellipse with axes of equal length.

Create a Planar Pin Pad

Note. Refer to Figure 7−18.

Rice. 7−18. Platform for planar output.

Setting Complex Stack Options

Setting parameters for a complex stack has a variety of options.

Set the parameters of the top pad of the complex stack c110_p130_h90

1) In the Options Pad Style panel, specify a name for the style in the list.

2) Click the Modify (Complex) button.

Rice. 7−19. Setting the parameters of the upper pad.

3) In the Modify Pad Style (Complex) panel (Fig. 7−19) in the Layers list window, select the layer corresponding to the top side of the printed circuit board – Top.

4) In the Shape list, select the required pad shape. In this case it is an ellipse.

5) Set the Width and Height values in the Pad Definition frame to 1.1 mm, as shown in Fig. 7−19.

6) In the Hole frame, set the diameter of the mounting hole to 0.9 mm.

7) Check the Plated box.

8) Setting the XOffset and YOffset values allows you to offset the mounting hole relative to the center of the pad, as shown in Fig. on right.

9) Checking the Prohibit Copper Pour Connections checkbox allows you to prohibit connecting the pad to metallization areas on signal layers.

10) Click the Modify button to save the entered parameters.

Set the parameters of the bottom pad of the complex stack c110_p130_h90

1) In the Modify Pad Style (Complex) panel (Fig. 7−19) in the Layers list window, select the layer corresponding to the bottom side of the printed circuit board – Bottom.

2) In the Shape list, select the pad shape – Polygon.

3) Click the Modify button. The Polygonal Pad Shapes panel will appear (Fig. 7−20).

Rice. 7−20. Setting polygon parameters.

4) Since no polygons have yet been defined in the project, only one function is available - Regular Polygons. Set the number of sides (Sides), circumscribed circle diameter (Diameter) and rotation angle (Rotation), as shown in Fig. 7−20.

5) Click the Update button to transform the shape and the OK button to end the dialog.

Set the parameters for connecting the stack to the internal metallization layers

1) In the Layers list window, select (Plane)

2) Set the pad parameters as shown in Fig. 7−21, a. The meaning of the entered parameters is revealed in Fig. 7−21, b.

Rice. 7−21. Connection to metallization layers.

3) Click the Modify button to save the entered parameters.

In addition to the default layers, you can add any layer existing in the project to the list of layers in the Modify Pad Style (Complex) panel by defining pad parameters for it.

Complete the list of layers

1) In the Modify Pad Style (Complex) panel (Fig. 7−19), expand the list of existing layers in the Layer list box.

2) Select any layer from the drop-down list, for example, Top Silk.

3) Select Target as the pad shape (see Table 7−6).

4) Set the width and height of the contact pad to 2 mm.

5) Click the Add button. The new layer will appear in the Layers list, as shown in Fig. 7−22.

Rice. 7−22. Adding a new layer.

Any newly added layer can be easily removed from the list. To do this, you need to select it with the cursor and press the Delete button.

Finish editing pad stacks

1) Remove the Top Silk layer from the list of layers.

2) In the Modify Pad Style (Complex) panel, click OK to complete the operation of creating a complex pad stack.

3) In the Options Pad Style panel, click OK to finish working with pad stacks.

4) Save the project to the Templates folder with the name PCB Settings.

Deleting and renaming created CP styles

Any newly created pad style can be removed from the list of pad styles. To do this, in the Options Pad Style panel, select the style to be deleted in the list and click the Delete button.

When deleting a style, the system issues a warning that this action cannot be canceled and asks for confirmation (Fig. 7−23).

By clicking the Purging Unused Pad Styles button in the Options Pad Style panel, you can immediately remove all unused pad styles from the list from the list. To perform this operation, the system also asks for a confirmation similar to that shown in Fig. 7−23.

To change the name of a style, you need to specify it in the list in the Options Pad Style panel and click the Rename button. In the Rename Style panel that appears in the New style name window (see Fig. 7−24), you need to enter a new style name.

Creating Via Styles

Via styles are specified using the Options/Via Style command. From a formal point of view, there are no differences from specifying pad styles. The dimensions of the contact pads at vias are smaller and their shape may not be as varied.

Create several styles (simple and complex) for vias yourself.

Note. Prefix "v" to the name of via stacks to distinguish them from pad stacks, for example, v_c090_h050

Creating blind holes

An interesting feature of the P-CAD system is the ability to create blind holes in pad and via stacks. To set the area of distribution of the hole, use the Modify Hole Range button on the Options Pad Style panel (see Fig. 7−15).

Rice. 7−25. Specifying the hole definition area.

In the Options Modify Hole Range panel that appears (Fig. 7−25) in the Hole Range Layers window, where the signal layers and metallization layers are displayed, you can specify the area of the hole. For example in Fig. 7−25 shows a hole connecting two internal signal layers. To specify the layers to be connected in the Hole Range Layers window, drag the cursor over their names while holding down the left mouse button.

Setting technological standards and design rules

It is convenient to determine the main technological parameters of the project using the Options/Design Rules command. This command is similar to that discussed earlier in Section 6, but unlike the circuit editor, its window has two additional tabs Layers for setting technological parameters on signal layers and metallization layers and Rooms for setting technological parameters for individual sections of the printed circuit board, the so-called rooms ( see Fig. 7−26).

Rice. 7−26. Setting general design rules.

Review the contents of the Options/Design Rules command tabs.

Saving technology settings

Information about technological design standards in the P-CAD system can be stored in a separate Design Technology Parameters file with the .dtp extension. This is quite convenient, since the data in this file can be replenished, edited and used by a circuit designer when working on a circuit in the Schematic editor, by a designer when working in the PCB editor, or by a library administrator when working in the package editor. Thus, at different stages of design, uniform rules and regulations are used.

Save the entered pad and via styles to the project's process parameters file

1) In the File menu, activate the Design Technology Parameters… command.

2) On the Design Technology Parameters panel that appears, click the Technology Filename button and find the “Amplifier.dtp” file in the project folders, which was created when performing subsection 6.13.

3) Uncheck Read-only File to allow data to be written to the file.

4) Open the General group (see Figure 7−27) and select the Pad Styles item in it.

5) Click the Update From Design button to record the pad stacks created in the current design (see Figure 7-27).

Rice. 7−27.Saving technological parameters

6) Highlight Via Styles and click the Update From Design button to write the current via styles to the process parameters file.

7) Close the Design Technology Parameters panel by clicking the Close button.

Lessons on P-CAD. Lesson 1

Launching the schematic editor (Schematic). Selecting and installing a system of units of measurement and drawing dimensions. Setting grid parameters. Creating new text styles. Editing existing text styles. Setting the width of lines and conductors. Configure display options. Setting up the keyboard and mouse. Setting up an object selection filter. Saving a project template.

The data in the current paragraph is generated for the subsequent “shoeing” of the component pins. Pads for component pins and vias can come in a variety of shapes and sizes. Therefore, for the element base used in development, the user creates his own libraries of stacks of pads and vias, which are saved in the Design Technology Parameters project technological parameters file (.dtp extension).

This file contains information about other project parameters - the values of permissible gaps, the structure of layers, properties and classes of individual circuits, etc.

To create a process parameters file in the P-CAD Pattern Editor, do the following:

run the Pattern/Design Technology Parameters command, enter the file name (for example Murgo) in the File name window, click the Open button, and then confirm the opening of a new (currently empty) technology parameters file;

uncheck the Read-only file checkbox, click the New Group button and enter the name of your project and click OK;

highlight the project name and to create sections of the process parameters file, click the New Section button (type of editable parameter group). The window shown in Fig. 2.14. Check the Pad Styles and Via Styles checkboxes and click OK;

Rice. 2.14. Design Technology Parameters... window

highlight the Pad Styles line, click the New Item button (new type of pad), enter the name of the pad to be created (the entered name should reflect some parameters of the stack being created, for example, the name smd2108 indicates that the pad is planar with dimensions of 2.1 mm X 0.8 mm, and the name dip17 means that the pad is through and its outer diameter is 1.7 mm) and click OK;

repeat the operation of naming the pads as many times as there are types of pads in your project (pads can be deleted or renamed if necessary). Note that the geometric shapes and dimensions of the contact pads for holes in the PCB are determined by the design and technological documentation in force at the enterprise.

The view of the window after carrying out these operations is shown in Fig. 2.15.

When the Read-only file checkbox in the Design Technology Parameters window is enabled, data cannot be edited.

N PCBs contain simple (Simple) and complex (Complex) stacks of pads and vias (Via Stacks). A pad stack is a file that contains a description of the pad graphics in the various PCB layers and the photoplotter aperture number.

Rice. 2.15. Project technological parameters window

Stacks for DIP components that have the same pad shape on all PCB layers, and stacks for planar lead components (SMD packages) that have pads on a single PCB layer form simple stacks. Components with planar pins are placed on the Top or Bottom layers (the graphics of the housings of these components are also specified on the same layers). Complex stacks on different layers of PCB can have different geometric shapes. The first pin stack of a component must be different (for example, square) from the other stacks of the same component.

To create (edit) stacks, execute the Options/Pad Style command (Fig. 2.16). In the Current Style region, there is usually only one pad stack at the start of operation - Default. Highlight the Default line, click the Sora button and in the Pad Name window enter the name of the new pad stack (for example, dip17) and click OK. The name of the new pad appears in the Current Style area. Similarly, you can sequentially enter the names (names for now!) of all the necessary stacks.

In Fig. Figure 2.16 shows examples of stacks, the names of which reflect the shape and size of the pads:

dip17 - round pad with a diameter of 1.7 mm;

DIP12 - round pad with a diameter of 1.2 mm;

plan2108 - planar platform measuring 2.1 x 0.8 mm;

REC1212 - square (rectangular) pad measuring 1.2 x 1.2 mm.

After highlighting the stack name and clicking the Modify (Simple) button, a menu for editing simple pad stacks opens (Fig. 2.17).

R
is. 2.16. Pad stacks

Rice. 2.17. Window for editing simple stacks

In the Tour area, select the pad type:

Thru - contact pad for pin output;

Torus - contact pad for planar output from the side where the component is installed on the PCB;

Bottom - pad for planar output on the component mounting side.

In the Plane Connection area, the type of contact pads is indicated when connecting them to continuous metallization layers:

Thermal - contact pad with a thermal barrier;

Direct - a solid contact pad, directly connected to the metallization layer.

In the Shape window list, the shape of the pad is set:

Ellipse - elliptical (circle);

Oval - oval;

Rectangle - rectangular;

Rounded Rectangle - rectangular with rounded corners;

Target - crosshair for drilling;

Mounting Hole - mounting hole.

The table shows the internal (d) diameters of the holes and diameters (D) of the contact pads for PCBs of the 4th accuracy class.

Table. Diameters (mm)

The geometric dimensions of the pads are set in the Widht (width), Height (height) and Diameter (drill hole diameter) windows. If the hole is metallized, then the Plated checkbox is selected in the Hole area.

In the Plane Swell area, the value of the gap between the metallization layer and the pads and vias not connected to it is set. This gap is maintained during automatic routing of connections on the printed circuit board. After all settings, click OK.

By selecting the desired stack name and clicking the Modify (Complex) button in the Options Pad Style (Complex) dialog box, complex pad stacks are edited (Fig. 2.18).

In the Layers window, sequentially indicate the names of the layers on which the stack pads will be placed. The names of the layers appear when the list of layers is expanded in the Layer window of the Pad Definition area, the desired layer is selected from the list and added to the field

Layers when you click on the Add button. In the Shape, Widht and Height windows, the Pad Definition areas indicate the shape of the pad on the selected layer, its width and height, respectively.

Rice. 2.18. Editing complex stacks

The Shape list contains thirteen options for pad shapes:

Poligon - pad defined by a polygon;

Thermal 2 Spoke - contact pad with two thermal barriers;

Thermal 2 Spoke/90 - contact pad with two thermal barriers rotated 90°;

Thermal 4 Spoke - contact pad with four thermal barriers;

Thermal 4 Spoke/45 - contact pad with four thermal barriers rotated at 45°;

Direct Connect - a pad with a direct connection to a continuous metallization layer.

Other options are the same as for contact pads with simple shapes.

When selecting a contact pad in the form of a thermal barrier, the values of the external and internal diameters of the pad are entered in the Outer Dia/Inner Dia windows that appear. The Spoke Width window specifies the width of the thermal barrier.

In the Hole area in the Diameter window, the diameter of the metallized/non-metallized (the Plated checkbox is on/off) hole connecting the PP layers is set. The offset of the center of the hole relative to the center of the photocoordinate aperture (horizontally - X Offset and vertically - Y Offset) is determined by the equipment used for making photomasks.

After finishing setting the parameters for each pad, click the Modify button.

P
After completing the data settings for the stack for all layers, click OK, and in the Options Pad Style window that appears (Fig. 2.16), to view stack sections (only for through holes!) of pads in all layers of the printed circuit board, click the Modify Hole Range button ( Fig. 2.19).

Figure 2.19. Cross section of pad stacks

Then, in the Styles area, select the name of the stack and view images of its sections across all previously installed PCB layers for it.

Via stacks are generated after executing the Options/Via Style command in the same way as pad stacks are generated.

The names of the design's via stacks are specified using the Pattern/Design Technology Parameters command (see Figure 2.15).

All generated stacks of pads can be placed on the working field of the PCB after executing the Place/Pad command of the P-CAD Pattern Editor program. This placement of stack pads is carried out to form the installation location of the component for the purpose of subsequent recording it in a library or in a separate file (PAT extension).

On the list Shape Thirteen options for contact pad shapes are indicated:

Polygon- contact area defined by the polygon;
Thermal 2 Spoke- contact pad with two thermal barriers;
Thermal 2 Spoke/90- contact pad With two thermal barriers rotated 90°;
Thermal 4 Spoke- contact area with four thermal barriers;
Thermal 4 Spoke/45- contact pad with four thermal barriers rotated by 45°;
Direct Connect- contact pad with direct connection to a continuous metallization layer.
Other options- as for contact pads with simple shapes.

When selecting a contact pad in the form of a thermal barrier in the appearing windows Outer Dia/Inner Dia The values of the external and internal diameters of the site are entered. In the window Spoke Width the width of the thermal barrier is set.

In area Hole in the window Diameter the diameter of metallized/non-metallized is set (the checkbox is turned on/off Plated) hole connecting the PP layers. Displacement of the center of the hole relative to the center of the photocoordinate aperture (horizontally - X Offset and vertically - Y Offset) is determined by the equipment used to make photomasks.

After finishing setting the parameters for each pad, press the button Modify.

After completing the data settings for the stack for all layers, press the button OK, and in the window that appears Options Pad Style(Fig. 2.16) to view stack sections (only for through holes!) pads in all layers of the printed circuit board, the button is pressed Modify Hole Range(Fig. 2.19).

Rice. 2.19. Cross section of pad stacks

Then in the area Styles select the name of the stack and view images of its sections across all previously installed layers of the printed circuit board.

Via Stacks are formed after the command is executed Options/Via Style similar to the formation of pad stacks.

Project via stack names are set by command Pattern/Design Technology Parameters(see Fig. 2.15).

All generated stacks of pads can be placed on the working field of the PCB after executing the command Place/Pad programs P-CAD Pattern Editor. This placement of stack pads is carried out to form the installation location of the component for the purpose of subsequent recording it in a library or in a separate file (extension PAT).

Illustrated tutorial on P-CAD. Manually creating a footprint Pad stack

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