Introduction
Designing the layout and circuitry of a printed circuit board (PCB) is a key step in developing an electronic product. The PCB provides the foundation for component assembly and enabling system operation. For those new to PCB design, the process can seem intimidating at first. However, by following a step-by-step approach, even beginners can learn the fundamentals of PCB design.
This article provides 16 easy steps to guide you in getting started with designing simple PCBs quickly.
Step 1: Have a Clear Design Idea
- Define the electronic product or device you want to build. This provides the requirements for the PCB design.
- Research similar products and circuits to guide the architecture.
- List out the key functions and components needed.
Having a clear design concept is vital before jumping into the PCB layout software.
Step 2: Select the Core Components
- Make a list of the major ICs and other critical components like microcontrollers, sensors, connectors etc.
- These provide the core functionality and drive the design.
- Check availability, datasheets, footprints and pricing.
- Order samples for prototyping.
Choosing the key components early provides a framework for the PCB design process.
Step 3: Find Reference Designs
- Many component vendors offer reference designs and sample circuits using their parts.
- These serve as a great starting point for circuit design.
- Download reference schematics and layouts where available.
Leveraging proven reference designs saves enormous time and minimizes risks.
Step 4: Learn the Design Software
- While experienced designers use specialized CAD tools like Altium or Cadence, beginners can start with easier programs.
- Free tools like EasyEDA, KiCAD or Eagle offer simpler entry points for new designers.
- Watch video tutorials to grasp the essentials of the tool’s interface and features.
Using the right design software from the start avoids a steep learning curve.
Step 5: Create a Schematic
- A schematic diagram visually represents the circuit connectivity.
- Arrange the symbols for each component and connect with wires to define the functions.
- Double check the pinouts match the datasheets.
The schematic captures the overall board circuitry in an intuitive graphical form.
Step 6: Add Power Supply Section
- Show input power ports, fuses, and connectors on the schematic.
- Use voltage regulators, capacitors and inductors to generate clean onboard supply rails.
- Define labels for all supplies like VCC, 3v3, 5V0 etc.
Including the power supply section is often the first step in transforming the schematic into a functional PCB design.
Step 7: Include Bypass Capacitors
- Add ceramic bypass capacitors close to every IC power pin.
- Values like 0.1uF, 10uF are typical. This filters noise on supplies.
- Correct power decoupling is vital for a robust design.
Bypass capacitors improve circuit stability and prevent erratic behavior.
Step 8: Add Support Components
- Include additional resistors, capacitors, diodes, crystals, LEDs, headers, testpoints etc. as needed.
- Choose suitable footprints and ratings.
- Review schematic for completeness.
Supporting components enable intended functioning of the core ICs.
Step 9: Design the PCB Layout
- With the schematic completed, the physical PCB layout design can begin.
- Group components logically, allocate power zones and route traces.
- Ensure adequate clearances and proper component orientations.
A cleanly laid out PCB ensures good signal quality, EMI and thermal performance.
Step 10: Choose the Right PCB Technology
- Select PCB characteristics like layers, sizes, dielectric material, copper thickness, traces/spaces etc.
- These affect the layout, manufacturability and cost.
- Match PCB technology used to circuit needs.
Designing with manufacturing capabilities in mind avoids delays and redesigns.
Step 11: Create a Bill of Materials
- Make a list of all components to procure for assembling the designed PCB.
- Include manufacturer part numbers, quantity, reference designators etc.
- Review for completeness.
The BOM facilitates PCB assembly and prototyping of the designed board.
Step 12: Review Design Rules
- Every PCB fabrication process has constraints like minimum trace width, clearance etc.
- The CAD tool checks rules. Review and resolve any violations.
- Adjust layout as needed fit manufacturing capabilities.
Following design rules avoids manufacturing issues or rejection.
Step 13: Add Silkscreen and Assembly Markings
- Silkscreen layer shows component outlines, text, logos and other markings printed on the PCB.
- Helps with visual identification post assembly.
- Check polarity markings, component IDs and orientations.
Silkscreen markings assist assembly, debugging and system operation.
Step 14: Generate Manufacturing Files
- Manufacturing files like Gerbers, drill data, BOM, assembly drawings etc. are needed for fabrication.
- CAD tools provide exports to standard file formats.
- Review files thoroughly before release.
Correct manufacturing data is vital for an error-free board fabrication.
Step 15: Order PCB Prototypes
- Use online PCB services for affordable quickturn prototyping.
- Review quoted costs and lead times before ordering.
- Share manufacturing files.
Test circuits with actual boards instead of just software simulations.
Step 16: Assemble and Test Boards
- With the PCB prototypes received, populate components following BOM.
- Test power-up, voltages, signals and intended functionality.
- Update design as needed to rectify any issues observed.
Thoroughly testing prototype boards verifies the design and avoids costly mistakes.
Conclusion
The prospect of designing a PCB from concept to completion can seem daunting for beginners. By following a structured, step-by-step approach, breaking down the design into smaller logical blocks, and leveraging the right software tools, even amateurs can get started with simple PCB layout and circuit design quickly. Hands-on testing of prototypes is key to progressively building up expertise. With practice, new designers gain the experience needed to bring more advanced electronic product ideas to fruition.
Key Takeaways
- Have a clear design idea and requirements before starting
- Select the core components early to guide design
- Leverage reference designs to accelerate learning
- Use beginner-friendly PCB design software
- Develop the schematic diagram first visually
- Include power supply, bypass capacitors and supporting components
- Follow design rules and PCB capabilities
- Add identifying silkscreen markings and labels
- Verify all outputs before manufacturing release
- Test prototypes to validate the design
Recommended Next Steps
To take your PCB design skills further:
- Create more advanced circuits using sensors, communication ICs, high speed interfaces etc.
- Learn key principles like impedance control, thermal management, EMI/ESD protection etc.
- Get familiar with your PCB manufacturer’s capabilities and process limitations
- Experiment with more complex component packages like BGAs
- Study example designs across various applications and circuits
- Join PCB design communities to connect with experts
With diligent practice and an systematic approach, PCB design skills can be readily developed.
