Step-by-step cadence PCB design tutorial

Cadence software provides a full toolkit that enables engineers and designers of electrical systems to develop and validate sophisticated designs for various applications.

Designers frequently do Printed circuit board design using Cadence (PCBs). To get started with Cadence PCB design, follow these simple steps:

Create a new project

• Launch the Cadence Allegro software program.
• Choose “File” and “New Project” from the main menu.
• Type a name for your project in the “Name” field of the “New Project” box that displays. By using the “Browse” option located next to the “Directory” section, you may also select a place for your project files.
• Choose the technology file you wish to utilize from the “Technology” section. The design guidelines, layers, and other features for your design are available in the technology file.
• Choose “PCB” under “Project Type” to create a printed circuit board.
• To start the new project, click the “OK” button. Then, the newly formed project will appear in the Allegro Project Management window.
• You may make a new schematic or layout file in the Allegro Project Manager window by right-clicking on the respective folder and choosing “New.” Likewise, by selecting “Import” from the context menu when you right-click on the relevant folder, you may easily import already-existing files.

Create a new schematic

• Start your computer’s Allegro Design Entry CIS program.
• Choose “File” then “New” from the main menu.
• Choose “Schematic” as the file type and select a place to store your file in the “New File” box that displays.
• In the “File Name” area, give your schematic file a name and click the “OK” button.
• The schematic canvas will be empty when the Allegro Design Entry CIS main window loads.
• Click the “Place Part” icon from the toolbar on the left-hand side of the display to add components to your schematic.
• Go through the various libraries to find the part you want to include in your schematic. Moreover, the search feature may help to locate components fast.
• Add the component by clicking on the desired place on the schematic canvas.
• Draw wires between the pins on various components using the “Place Wire” tool to connect them.
• Click the “Annotate” icon from the toolbar and choose “Auto-Annotate” to annotate your schematic.
• By choosing “File” and then “Save,” you may save your schematic file.

Draw your circuit

To draw your circuit using Cadence Allegro, follow these steps:

• Launch the Allegro Design Entry CIS program, then follow the instructions in the preceding answer to generate a new schematic.
• Use the “Place Part” tool to add parts to your schematic. Components can be selected from libraries or made from scratch.
• Use the “Place Wire” tool to join the components together. You may also utilize other devices like buses or nets to link several pins.
• Include symbols for ground and power in your circuit. These symbols are available in libraries, or you may make your unique symbols.
• You may annotate your circuit using the “Annotate” tool and the necessary parameters.
• Make a netlist and save your schematic file. We can make the PCB layout using a netlist, which lists all the electrical connections in your circuit.
• Create a layout from your schematic using the Allegro PCB Editor. Components may be added and put on the board, and we can route traces between them.
• Run simulations and conduct design rule checks to validate and confirm your design.
• Produce output files for manufacturing, including drill files, assembly drawings, and Gerber files.

Remember to adhere to standard practices for circuit design, such as keeping traces short and preventing signal crosstalk.

Assign footprints

Assigning footprints to components in the PCB design process is crucial because it guarantees that the components are positioned and wired up properly on the PCB layout. Here are the processes for using Cadence Allegro to assign footprints to components:

• Launch Allegro PCB Editor on your computer, then import the design file.
• Choose “Place” and then “Component” from the main menu.
• Select the component you wish to give a footprint to in the “Place Component” dialog that displays.
• Choose the suitable footprint from the available libraries by clicking the “…” button in the “Footprint” section.
• To give the component the chosen footprint, click the “OK” button.
• For each of the components in your design, repeat these procedures.
• Using the “Place” and “Move” tools, you may arrange each component on the PCB layout after giving them all a set of footprints.
• The “Route” tool may create traces that link the component pins once positioned.
• Once your layout is complete, you may run a design rule check to ensure your design complies with all relevant requirements.
• Lastly, create manufacturing output files such as assembly drawings, drill files, and Gerber files.

Choose the proper footprints to guarantee that your components fit on the PCB and can be soldered correctly. It’s also crucial to check that the component’s pinout and the footprints are the same.

Create a netlist

The electrical connections in your design are in a netlist. It is a critical stage in the design of a PCB since it gives the data required to produce the physical layout of the PCB. Using Cadence Allegro, follow these steps to generate a netlist:

• Launch Allegro Design Entry CIS and select the schematic file.
• Choose “Tools” from the main menu, then “Build Netlist.”
• Choose the best parameters for your design from the “Create Netlist” window that displays, including the netlist format and where to save the netlist file.
• Click the “Create” button to produce the netlist.
• When the netlist is ready, Allegro PCB Editor may help to design the PCB layout. To design the actual architecture of the PCB, the netlist will offer details about the components and their connections.
• It’s crucial to make sure the netlist is accurate before utilizing it to generate the PCB layout. To achieve this, you may conduct simulations and a design rule check to ensure the circuit works as planned.
• You may use Allegro PCB Editor to construct the PCB layout after you have checked the netlist.

To ensure that the physical layout follows the intended circuit design, always remember to update the netlist anytime you modify your schematic or PCB layout.

Create a PCB layout

Placing the components and directing the traces to link them are steps in creating a PCB layout. Using Cadence Allegro, follow these steps to produce a PCB layout:

• Launch Allegro PCB Editor and add the netlist your design created.
• Choose “Place” and then “Component” from the main menu. Next, put the components on the PCB layout, ensuring they are positioned and spaced appropriately per your design specifications.
• If necessary, reposition the components using the “Move” tool.
• Connect the component pins with traces using the “Route” tool. You may also employ additional tools like differential pairs, vias, and teardrops to improve your routing.
• Use design guidelines to ensure the traces have proper spaces and prevent short circuits and other mistakes.
• To add ground and power planes to your PCB layout, use the “Plane” tool. These planes aid in supplying the components with a steady power source and a ground connection.
• Once your PCB layout is complete, conduct a design rule check to ensure your design complies with all relevant requirements.
• Create manufacturing output files, such as drill files, assembly drawings, and Gerber files.

Don’t forget to make your PCB layout as manufacturable as possible by reducing the amount of vias, eliminating right-angle traces, and ensuring the traces have enough space between them and other components.

Route traces

The crucial process of routing traces establishes the electrical connections between components and guarantees the circuit’s proper operation. The following are the procedures for routing traces in Cadence Allegro:

• Launch Allegro PCB Editor and drag your PCB layout into it.
• From the toolbar, choose the “Route” tool.
• Click the trace’s beginning point and move the pointer to the conclusion. It will take the shortest path automatically when routing the trace.
• If required, bend the trace using the “Bend” tool.
• To link traces between the PCB’s various layers, use the “Via” tool.
• To make teardrops at the intersections of traces and vias, use the “Teardrop” tool. This helps to lower the possibility of solder fractures and improves the PCB’s dependability.
• Use design guidelines to ensure the traces have proper spacing and prevent short circuits and other mistakes. The design guidelines can change to suit your unique requirements.
• To streamline the routing and reduce the number of bends and vias, use the “Clean Up” tool. This lowers the cost of production and raises the PCB’s dependability.
• Once you route the traces, perform a design rule check to ensure your design complies with all prerequisites.
• Create manufacturing output files, such as drill files, assembly drawings, and Gerber files.

Do not forget to optimize your trace routing for signal integrity by avoiding crossing signal traces, reducing trace length, and employing differential pairs for high-speed signals. As well as preventing routing traces over delicate parts like crystal oscillators and high-frequency filters, it’s crucial to ensure the traces have enough space between them and other components.

Add text and graphics

Your PCB layout may benefit from adding text and images to communicate key points better and increase design readability. Using Cadence Allegro, use these steps to add text and graphics:

• Launch Allegro PCB Editor and drag your PCB layout into it.
• Choose “Place” and “Text” from the main menu to add text to your PCB layout.
• Enter the required text in the dialog box that displays after clicking on the position where you want the text to appear. The text’s font, size, and color may all be changed to suit your needs.
• If necessary, reposition the text using the “Move” tool.
• Choose “Place” from the main menu, followed by “Graphics,” to add graphics to your PCB layout.
• Decide what graphic you want to include, such as a circle, rectangle, or line.
• Click on the area where you should place the graphic, then use the corresponding tool to change its dimensions.
• If necessary, reposition the graphic using the “Move” tool.
• Use design principles to ensure the text and visuals do not obstruct the component placement and routing.
• Lastly, make a design rule check to ensure your design complies with all relevant requirements.
• Create manufacturing-related output files, such as assembly drawings, drill, and Gerber files.

Remember that the language and visuals should be clear and simple to read and should not obstruct the electrical connections or affect the production process. Using text and visual styles that are acceptable for your design needs and brand guidelines is also crucial.

Check your design

To make sure that the circuit will operate as intended and to prevent mistakes during manufacturing, checking your design is an important stage in the PCB design process. These are the procedures for utilizing Cadence Allegro to check your design:

• Do a design rule check (DRC) to ensure your design complies with all relevant requirements. The DRC looks for various mistakes, including shortness, openings, overlap, spacing violations, etc.
• Check your design for electrical faults using the “ERC” (electrical rule check) tool. This looks for loose nets, missing connections, and other electrical problems.
• To look for problems with signal quality, use the “Signal Integrity” analysis tool. Due to its ability to detect possible difficulties with reflections, crosstalk, and other signal integrity concerns, this is particularly crucial for high-speed digital architectures.
• Do a “3D View” of your design to look for mechanical snags between parts and the PCB enclosure.
• Verify that each component’s footprint corresponds to the one you are utilizing. You may print off a duplicate of your design to compare the component footprints to the printed version.
• Verify again that the netlist fits your schematic and PCB layout.
• Ensure your design complies with all requirements, including safety and electromagnetic compatibility (EMC) standards.
• Finally, have someone else check over your design to be sure you didn’t miss any typos or other problems.

These procedures will help you ensure your design is flawless and prepared for production. Always double-check your design before submitting it for production since mistakes made during the design phase are far simpler to fix than those made after manufacturing.

Export your design

The last stage in the design process is exporting your PCB design, which entails creating output files that manufacturers may utilize to make your PCB. To export your design using Cadence Allegro, follow these steps:

• Launch Cadence Allegro PCB Editor and open your design.
• Click “Export” from the “File” menu.
• Decide the file type you wish to export, such as ODB++, NC drill, or Gerber files.
• Choose which layers you wish to export. The particular specifications set out by your manufacturer will determine this.
• Decide whether you want to use inches or millimeters as your units of measurement.
• Set the output directory, which will hold the stored files.
• Choose any extra parameters that might be necessary, such as the drill sizes or the list of available apertures.
• To create the output files, click “Export.”
• Check the exported files to ensure they adhere to your manufacturer’s specifications.
• Lastly, deliver the exported files and any extra supporting information, including assembly drawings and a bill of materials, to your manufacturer (BOM).

By following these procedures, you can ensure that your PCB design is prepared for manufacturing and that the manufacturer has all the information required to create your PCB appropriately.

Advantages of designing PCB using Cadence

Using software tools like Cadence Allegro to design a printed circuit board (PCB) provides several benefits over conventional manual techniques. The following are some of the key benefits of utilizing Cadence while designing PCBs:

Faster design process:

Various design automation solutions from Cadence Allegro, including auto-routing, schematic capture, and design rule verification, can assist in accelerating the design process. As a result, your design will finish more quickly, saving you both time and money.

Improved accuracy:

Cadence Allegro, a computer-aided design (CAD) program, eliminates the possibility of human mistakes that might arise with manual design approaches. Consequently, we produce more precise designs, lowering the possibility of manufacturing mistakes.

Better collaboration:

Collaborating on complicated designs using Cadence Allegro is simpler since it enables numerous designers to work on the same project simultaneously. This may enhance design quality, decrease mistakes, and accelerate the design process.

More flexibility:

Cadence Allegro allows you to adjust your design and make modifications as needed without having to start over. As a result, it will be simpler to iterate on your design and will assist in increasing its quality.

Improved documentation:

Cadence Allegro automatically creates thorough documentation, including bills of materials and assembly drawings (BOM). As a result, it lessens the possibility of production problems and ensures the accurate manufacturing of your design.

Better signal integrity:

Tools for assessing signal integrity problems, including reflections, crosstalk, and other high-speed signal problems, are provided by Cadence Allegro. This can enhance the functionality of your circuit and lessen the possibility of signal mistakes.

Design reuse:

Using pre-existing designs is simple with Cadence Allegro, which may help you save time and money on upcoming projects. As a result, this might be very helpful for businesses that generate comparable goods or product lines.

Manufacturing optimization:

Cadence Allegro offers capabilities for manufacturing design optimization, such as reducing the number of drill holes and improving component positioning. This might lower the production cost and increase your PCB’s dependability.

Advanced features:

Cadence Allegro offers several cutting-edge capabilities, including simulation, design rule validation, and 3D visualization. So, these tools can assist in enhancing the precision and quality of your design and simplify optimizing it for specific applications.

Better product quality:

Cadence Allegro’s assistance in minimizing mistakes and enhancing design correctness may enhance the end product’s quality. As a result, this can lower warranty and repair expenses while increasing customer satisfaction.