Altium Design：Getting Started with PCB Design

Welcome to the world of electronic product development environment in Altium software. This tutorial will get you started by creating a simple PCB project based on an astable multivibrator design. If you are new to Altium software then it is worth reading the article The Altium Designer Environment, for an explanation of the interface, information on how to use panels, and managing design documents.

To learn more about a command, dialog, object or panel, press F1 when the cursor is over that item.

The design you will be capturing, and then designing a printed circuit board (PCB) for, is a simple astable multivibrator. The circuit is shown below, it uses two 2N3904 transistors configured as a self-running astable multivibrator.

[url=http://techdocs.altium.com/sites/default/files/wiki_attachments/231428/Dlg_NewProject.png]
Create the new project in the required location.

Next we will add a new schematic sheet to the project. It is on this schematic we will capture the astable multivibrator circuit.

Create a new schematic sheet by completing the following steps:

When the blank schematic sheet opens you will notice that the workspace changes. The main toolbar includes a range of new buttons, new toolbars are visible, the menu bar includes new items and the Sheet panel is displayed. You are now in the Schematic Editor. You can customize many aspects of the workspace. For example, you can reposition the panels and toolbars or customize the menu and toolbar commands.

The first thing to do before you start drawing your circuit is to set up the appropriate document options. Complete the following steps.

You can activate any menu by pressing the menu accelerator key (the underlined letter in the menu name). Subsequent menu items will also have accelerator keys that you can use to select that item.

For example, the shortcut for selecting the View » Fit Document menu item is to press the V key followed by the D key.

Additionally, many submenus, such as the Select menu (in the Edit menu), can be called directly. For example, to activate the Edit » Select » Touching Line command, you need only press the S key (to call up theSelect menu directly) followed by the L key.

Next we will set the general schematic editor preferences.

To manage the thousands of components and models that are available, the Schematic Editor includes powerful library searching capabilities. Although the components we require are in the default installed libraries, it is useful to know how to search through all libraries to find components. Work through the following steps to locate and add the libraries you will need for the tutorial circuit.

First we will search for the transistors, both of which are type 2N3904.

The Libraries Search dialogs can search across folders on the hard drive, or libraries already installed in the software.

Library searching is actually performed using queries - a feature supported by the query engine that underlies the schematic and PCB editors. In the Libraries Search dialog, switch to the Advanced mode to examine the query. The query generated by your search configuration should be (Name LIKE '*3904*'), if it is not, type this string in and click Search again.

Filtering the library for components with the string 3904 in their name.

The first components we will place on the schematic are the two transistors, Q1 and Q2. Refer to the rough schematic sketch shown above for the general layout of the circuit.

Do not place the transistor yet!

[url=http://techdocs.altium.com/sites/default/files/wiki_attachments/231428/Dlg_ComponentProperties_ParamMapping.png]
Enter the Designator and Value, and map the Value into the Comment field, so that it transfers to the PCB.

The circuit with the transistors and resistors placed.

Note, components being simulated may have a number of simulation properties that can be defined (eg, a resistor has 1, a BJT has 5, and a MOSFET has 13) - these properties are defined by using Parameters. If you wanted to simulate this circuit then the resistor value must be defined as a Parameter, whose name is Value and whose value is the resistance.

If the circuit being captured is for both simulation and PCB layout, rather than enter the value twice (in the parameter called Value and then again in the Comment field), you can use the technique described above, to map any parameter's string into the Comment field. This feature is called indirection, if you click to display the Comment field dropdown list you will see that the software has automatically built a list of all current parameters, in case you want to map the value of one of them into the Comment field. String indirection can be used to map parameters in other situations too, such as mapping Document or Project parameters (such as ProjectTitle) into strings placed in a schematic template.

Now place the two capacitors.

Circuit with the capacitors also placed.

The last component to be placed is the connector, located in Miscellaneous Connectors.IntLib. This integrated library is normally already installed, if it is not:

Once the Miscellaneous Connectors.IntLib has been installed:

Circuit with all parts placed.

You have now placed all the components. Note that the components shown in the figure below are spaced so that there is plenty of room to wire to each component pin. This is important because you can not place a wire across the bottom of a pin to get to a pin beyond it. If you do, both pins will connect to the wire. If you need to move a component, click-and-hold on the body of the component, then drag the mouse to reposition it.

Wiring is the process of creating connectivity between the various components of your circuit. To wire up your schematic, refer to the sketch of the circuit, or the animation shown below, and complete the following steps:

Wiring the schematic.

Hold Ctrl as you click and drag to maintain connectivity.

Each set of component pins that you have connected to each other now form what is referred to as a net. For example, one net includes the base of Q1, one pin of R1 and one pin of C1. Each net is automatically assigned a system-generated name, which is based on one of the component pins in that net.

To make it easy to identify important nets in the design, you can add Net Labels to assign your preferred name. To place net labels on the two power nets:

   
The net label in free space (left image) and positioned over a wire (right image), note the red cross.

The completed schematic, ready to check for errors.

Congratulations! You have just completed your first schematic capture. Before we turn the schematic into a circuit board we need to configure the project options, and check the design for errors.

Project outputs, such as assembly, fabrication outputs and reports can be set up from the File and Reports menus. These settings are also stored in the Project file so they are always available for this project. Alternatively you can set up output options in an Output Job file (File » New » Output Job File). See [url=http://techdocs.altium.com/print/231428#DocumentationOutputs]Documentation Outputs for more information.

When the project is compiled, comprehensive design and electrical rules are applied to verify the design. When all errors are resolved, the compiled schematic design is ready to be transferred to the target PCB document by generating a series of Engineering Change Orders (ECOs). Underlying this process is a comparator engine that identifies every difference between the schematic design and the PCB, and generates an ECO to resolve each difference. This approach of using a comparator engine to identify differences means you not only work directly between the schematic and PCB (there is no intermediate netlist file used), it also means the same approach can be used to synchronize the schematic and PCB at any stage during the design process. The comparator engine also allows you to find differences between source and target files and update (synchronize) in both directions.

Schematic diagrams are more than just simple drawings - they contain electrical connectivity information about the circuit. You can use this connectivity awareness to verify your design. When you compile a project, the software checks for errors according to the rules set up in the Error Reporting and Connection Matrix tabs of the Options for Project dialog. When you compile the project any violations that are detected will display in the Messages panel.

The Error Reporting tab in the Options for Project dialog is used to set up design drafting checks. The Report Mode settings show the level of severity of a violation. If you wish to change a setting, click on a Report Mode next to the violation you wish to change and choose the level of severity from the drop-down list. For this tutorial we will use the default settings in this tab.

[url=http://techdocs.altium.com/sites/default/files/wiki_attachments/231428/Dlg_ProjectOptions_ClassGen-highlight.png]
Component and net classes can be generated from the schematic, as well as placement rooms.

When the design is transferred to the PCB, component classes, net classes, and placement rooms can be generated automatically. This is particularly useful for a well-structured hierarchical design, creating a component class and component placement room from each sheet, and a net class from each bus. This default behavior is not necessary for this simple design, to disable this:

[url=http://techdocs.altium.com/sites/default/files/wiki_attachments/231428/Pnl_Messages1.png]
Use the Messages panel to locate and resolve design errors - double-click on an error to pan and zoom to that object.

When you double click on an error in the Messages panel:

Before we finish this section of the tutorial, let's fix the error in our schematic.

Schematic capture is now complete, time to create the PCB!

Main article: Preparing the Board for Design Transfer

Before you transfer the design from the Schematic Editor to the PCB Editor, you need to create the blank PCB with at least a board outline. There are a number of ways of creating the blank board, including:

For this tutorial, the last approach will be used.

To create a new PCB, based on a template:

[url=http://techdocs.altium.com/sites/default/files/wiki_attachments/231428/Mode_2D.png] [/url]
Switch from 2D to Board Planning Mode so you can redefine the board shape.

[url=http://techdocs.altium.com/sites/default/files/wiki_attachments/231428/RedefineBoardShape1.png] [/url]
Resizing the board shape to the required size (note the editing cursor in the left image), then move the shape to the center of the page.

[url=http://techdocs.altium.com/sites/default/files/wiki_attachments/231428/DragPcb1.png] [/url] [url=http://techdocs.altium.com/sites/default/files/wiki_attachments/231428/DragPcb3.png]
Drag and drop the PCB file onto the project file to make it part of the project. The reverse process can be used to remove a file from the project.

The process of transferring a design from the capture stage to the board layout stage is launched by selecting Design » Update PCB Document Multivibrator.PcbDoc from the Schematic Editor menus, or Design » Import Changes from Multivibrator.PcbDoc from the PCB Editor menus - when you do the design is compiled and a set of Engineering Change Orders is created, that will perform the following steps:

Before transferring the schematic information to the new blank PCB, you should always make sure all the related libraries for both schematic and PCB are available. Since only the default installed integrated libraries are used in this tutorial the required libraries are already available, which means the footprints are available.

You are now ready to transfer the design from schematic capture to PCB layout. To transfer the schematic information to the target PCB:

An ECO is created for each change that needs to be made to the PCB so that it matches the schematic.

Once all of the ECOs have been executed the components and nets will appear in the PCB workspace, just to the right of the board outline. Note that some of the component pads may be highlighted in green and there may be white outline circles around some of the silkscreen - these indicate design rule violations:

Violation markers can be cleared at any time using the Tools » Reset Error Markers command, and the design re-checked at any time using the Tools » Design Rule Check command.

Note that the PCB Editor is capable of rendering the PCB design in both 2 Dimensional and 3 Dimensional modes. 2D mode is a multi-layered environment that is ideal for normal PCB design tasks, such as placing and routing the components. 3D mode is useful for examining your design both inside and out as a full 3D model. Note that 3D mode does not provide the same range of functionality available in 2D mode. You can switch between 2D and 3D modes through View » 2D Layout Mode or View » 3D Layout Mode (shortcuts: 2 (2D), 3 (3D)).

Before we start positioning the components on the board we need to configure certain PCB workspace and board settings, such as the layers, grids and design rules.

As well as the the layers used to fabricate the board, including: signal, power plane, mask and silkscreen layers, the PCB Editor also supports numerous other non-electrical layers. The layers are often grouped in the following way:

The display attributes of all layers are configured in the View Configurations dialog (Design » Board Layers and Colors, or press the L shortcut).

[url=http://techdocs.altium.com/sites/default/files/wiki_attachments/231428/Dlg_LayerStackManager3D.png]
The properties of the physical layers are defined in the Layer Stack Manager.

We need to ensure that our placement grid is set correctly before we start positioning the components. All the objects placed in the PCB workspace are aligned on the snap grid. This grid needs to be set to suit the routing technology that we plan to use.

The tutorial uses standard imperial components that have a minimum pin pitch of 100mil. We will set the snap grid to an even fraction of this, say 50mil or 25mil, so that all component pins will fall on a grid point when placed. Also, the track width and clearance for our board are 12mil and 13mil respectively (the default values used by the PCB Board Wizard ), allowing a minimum of 25mil between parallel track centers. The most suitable snap grid setting would, therefore, be 25mil.

To set the snap grid, complete the following steps:

Set the Snap Grid to 25 mils.

Let's set some other options that will make positioning components easier.

The PCB Editor is a rules-driven environment, meaning that as you perform actions that change the design, such as placing tracks, moving components, or autorouting the board, Altium Designer monitors each action and checks to see if the design still complies with the design rules. If it does not, then the error is immediately highlighted as a violation. Setting up the design rules before you start working on the board allows you to remain focused on the task of designing, confident in the knowledge that any design errors will immediately be flagged for your attention.

The design rules fall into 10 categories, which can then be further divided into design rule types. The design rules cover electrical, routing, manufacturing, placement and signal integrity requirements.

The Routing Width design rule, which was configured by the PCB Board Wizard when the board was created, with a new rule about to be created.

One of the powerful features of Altium Designer's design rule system is that multiple rules of the same type can be defined, each targeting different objects, or a subset of objects already targeted by another rule. The exact set of objects that each rule targets is defined by that rule's Scope. The order that rules of the same type are applied is determined by the Rule Priority. For example, you could have a width constraint rule for the whole board (meaning all nets must be routed this width), a second width constraint rule for the ground net (this rule would have a higher priority, overriding the previous rule), and a third width constraint rule for a particular connection on the ground net (which has the highest priority, overriding both of the previous rules). The Rule priority is displayed when you click on the rule type in the tree on the left of the dialog, in this example you would click on Width to display a summary of all width-type rules, including their Priority setting.

Currently there is one width constraint rule for your design, which applies to the whole board (width = 12mil). We will now add a new width constraint rule for the 12V and GND nets (width = 25mil). To add new width constraint rules, complete the following steps:

The new rule to resolve the clearance violation between the transistor pads.

Now we can start to place the components in their right positions.

Components placed on the board with new footprints.

With everything positioned, it's time to do some routing!

Main articles: Getting ready to route, Interactively Routing a Net, Modifying Existing Routing

Routing is the process of laying tracks and vias on the board to connect the component pins. Altium Designer makes this job easy by providing sophisticated interactive routing tools as well as the Situs topological autorouter, which optimally routes the whole or part of a board at the click of a button.

While autorouting provides an easy and powerful way to route a board, there will be situations where you will need exact control over the placement of tracks. In these situations you can manually route part or all of your board. In this section of the tutorial, we will manually route the entire board single-sided, with all tracks on the bottom layer. The Interactive Routing tools help maximize routing efficiency and flexibility in an intuitive way, including cursor guidance for track placement, single-click routing of the connection, pushing or walking around obstacles, automatically following existing connections, all in accordance with applicable design rules.

We will now place tracks on the bottom layer of the board, using the ratsnest (connection lines) to guide us. Tracks on a PCB are made from a series of straight segments. Each time there is a change of direction, a new track segment begins. Also, by default Altium Designer constrains tracks to a vertical, horizontal or 45° orientation, allowing you to easily produce professional results. This behavior can be customized to suit your needs, but for this tutorial we will use the default.

Keep in mind the following points as you are placing the tracks:

Altium Designer's Interactive Routing tool supports a number of different modes, with each mode helping the designer deal with particular situations. Press the Shift + R shortcut to cycle through these modes as you interactively route - note that the current mode is displayed on the Status bar.

The available modes include:

Main article: Modifying Existing Routing

Given that board design is a highly fluid process, you will find that the routes that seemed great today may no longer be suitable tomorrow, so it is essential to understand how to re-route and modify existing routes.

Because we originally defined our board as being double-sided in the PCB Board Wizard, you could manually route your board double-sided using both the top and bottom layers. To do this, un-route the board by selectingTools » Un-Route » All from the menus. Start interactive routing as before, to switch routing layers press the * key on the numeric keypad to toggle between the layers while placing tracks. Altium Designer will automatically insert a via (in accordance with the Routing Via design rule) as necessary when you change layers.

To modify an existing route, there are two approaches: reroute, or re-arrange.

There is no need to un-route a connection to redefine its path, simply select Place » Interactive Routing and start re-routing, the Loop Removal feature will automatically remove any redundant track segments. Altium Designer includes a net analyzer that automatically analyses the route path as you work and removes redundant segments and vias. You can start and end the new route path at any point, swapping layers as required. Note that there are situations where you may want to create loops, for example power net routing. If necessary, Loop Removal can be disabled for an individual net by editing that net in the PCB panel. To access the option set the panel to Nets mode, then double click on the net name in the panel to open the Edit Net dialog. Loop Removal is enabled in the PCB Editor - Interactive Routing page of the Preferences dialog.

You can interactively more or slide track segments across the board to make room for new routes. Altium Designer will automatically maintain the 45/90 degree angles with connected segments, shortening and lengthening them as required. To slide a segment:

Main article: Situs Autorouting Essentials

To see how easy it is to autoroute with Altium Designer, complete the following steps:

Altium Designer is a rules-driven board design environment, in which you can define many types of design rules to ensure the integrity of your board. Typically, you set up the design rules at the start of the design process and then verify that the design complies with the rules as you work through the design, and at the end of the design process.

Earlier in the tutorial we examined the routing design rules and added a new width constraint rule targeting the power nets, and a new clearance constraint rule for the transistor pads. We also noted that there were already a number of rules that had been created by the PCB Board Wizard, and that there were some existing design rule violations against these default rules.

To verify that the routed circuit board conforms to the design rules, we will now run a Design Rule Check (DRC):

A clean DRC report, showing zero warnings and zero violations.

Well done! You have completed the PCB layout and are ready to produce output documentation. Before doing that, we'll explore Altium Designer's 3D capabilities.

Related articles: Working with the Board Insight System, ECAD - MCAD Integration

Now that your board design is complete, let's examine it as a 3 dimensional object. To switch to 3D, select View » 3D Layout Mode (shortcut: 3), or select a 3D view configuration from the list on the PCB Standardtoolbar. The board will display as a 3 dimensional object.

You can fluidly zoom the view, rotate it and even travel inside the board using the following controls:

​[/url]

The Multivibrator PCB fully assembled into a two part housing assembly, inside Altium Designer.

Related article: Design to Manufacturing

Now that you've completed the design and layout of the PCB, you will want to produce output documentation to get the board reviewed, manufactured and assembled. Output settings can be configured from within the PCB editor, these settings will be stored in the project file. Output settings can also be configured in an Output Job File, a dedicated output settings document.

The advantages of using an Output Job (OutJob) include:

Netlists describe the logical connectivity between components in the design and is useful for transporting to other electronics design applications.

For more information on using the OutputJob Editor, see Design to Manufacturing.

For more information on publishing to PDF, see Publish to PDF.

Each Gerber file corresponds to one layer of the physical board - the component overlay, top signal layer, bottom signal layer, top solder mask layer, and so on. It is advisable to consult with your board fabricator to confirm their requirements before supplying the output documentation required to fabricate your design.

Configure the Gerber settings to suit the design.

To configure the Gerber files for the tutorial PCB:

For more information about Fabrication Outputs and configuring your Gerber Outputs, see [url=http://techdocs.altium.com/node/231704]Fabrication Outputs.

You will now create a Bill of Materials (BOM) for the tutorial PCB.

Congratulations! You have completed the PCB design process.

Further Explorations

This tutorial has introduced you to just some of the powerful features of Altium Designer. We've captured a schematic and designed and routed a PCB, but we've only just scratched the surface of the design power provided by Altium Designer. Once you start exploring Altium Designer, you will find a wealth of features to make your design life easier.

To demonstrate the capabilities of the software, a number of example files are included. You can open these examples in the normal way by selecting File » Open Project from the menus and then navigating to the Examplesfolder of your Altium Designer installation. As well as the board design examples in this folder, there are a number of sub-folders with examples that demonstrate specific features of Altium Designer.