How To Design PCB Boards: From the Schematic to Final Board Layout

In this article, we will look at how to design PCB boards.

The first step towards building an electronic circuit is creating and testing its functionality, usually using a microcontroller.

But after that, you must transfer this prototype into a printed wiring board.

And this process begins with designing the circuit board.

So how do you get started? And what are the steps to get the final design?

Let’s look at how to design PCB boards from scratch.

PCB Design Process

This process has four steps.

  1. Creating the schematic
  2. Do the pre-layout
  3. Layout the PCB
  4. Generate production files

Creating the PCB Schematic

A schematic diagram is similar to a circuit diagram because it shows the elements used in the system and their interconnection.

The schematic shows these elements using circuit symbols (abstract, graphic representations of the electronic components).

So overall, generating a circuit schematic gives a logical circuit representation for your unique electronic product.

A schematic/circuit diagram

A schematic/circuit diagram

Depending on the PCB design software, you might have to follow these steps to draw the schematic diagram.

Generate Circuit Symbols

Some PCB design software comes with libraries containing pre-drawn circuit symbols.

But others require you to use closed shapes like triangles and rectangles as canvases to create component symbols.

So you can customize these shapes by including pins and their numbers.

Pins indicate the connection points for components, showing the power in/out and signal in/out channels.

Including pins goes hand-in-hand with numbering them.

These numbers ensure the electrical connections link correctly on the PCB copper traces.

Next, include the reference designators for every symbol (component) in the schematic diagram.

It can be as simple as C1, C2, and C3 for capacitors or include the following data.

  • Value
  • Part number
  • Category
  • Manufacturer
  • Supplier

The last step in generating circuit symbols is assigning a footprint (component size).

Most components come in standard packages, making it easy to find their size online.

If unavailable, create the part footprint manually in your PCB designer software.

Connect the Symbols

Once done with the component symbols, connect them as required to form the circuit diagram.

The wiring connections might overlap.

And the standard practice is to have a junction dot for every intersection sharing an electrical connection.

But don’t place a dot if the connection lines overlap and there’s no electrical connection at the junction.

A circuit schematic diagram (note the junctions with dots and those without)

A circuit schematic diagram (note the junctions with dots and those without)

After connecting all circuit components, mark the vital signals, such as impedance traces.

And ensure you isolate these individual traces, then place the markings.

For instance, you can have 100Ω or 50Ω SE (Single Ended).

Remember to mark and identify the power and ground copper traces before concluding.

Link Footprints To Symbols

Each circuit component has a footprint, and as stated earlier, you can create it manually if unavailable.

You’ll have to link this footprint to the circuit symbols in the schematic diagram.

The data will be handy when you transfer the schematic info to the board layout. 

Generate Netlist

A net is the interconnection between two components.

So a netlist is a list describing the electrical connections in the circuit. 

In this case, the netlist will contain information about the component name.

Also, it will show the pad the component connects to on the circuit board.

The other function of the netlist is to assign serial numbers to the electrical connections in order.

An embedded system’s electronic circuit schematic

An embedded system’s electronic circuit schematic

You can edit, delete, or add entries, like component pads, to this list using the Netlist manager.

Do A Netlist Check

After generating and exporting the netlist, you’ll get a netlist document with a .net extension name.

We recommend doing a net-by-net verification on the schematic to ensure the nets interconnect as required.

Generate the Bill of Materials

Once the nets check out, generate the BOM, a list of all the components on the schematic diagram.

This bill of materials will show all the materials or parts required to build the circuit board.


The pre-layout stage defines the processes for transitioning from a schematic diagram to a PCB layout. It includes the following steps.

A close-up image of a PCB wiring diagram

A close-up image of a PCB wiring diagram

BOM/Board Materials Validation

Validating this materials list means checking if all the required components are available before manufacturing begins.

The process verifies if:

  • Manufacturing Part Numbers (MPN), Vendor Part Numbers (VPN), and Parts Quantities are correct.
  • The list contains marked DNI (Do Not Install) components.
  • Reference designators match those in the schematic diagram.

Layer Stackup Design

Most designers contact their fab houses or contract manufacturers to get assistance in making the correct stackup arrangement.

Designing this stackup before laying out the board is critical because it contains these parameters.

  • PCB substrate material (I-Speed, FR4, Rogers, etc.). The material depends on factors like environmental factors and operating frequency.
  • Copper layer thickness
  • Number of power and signal layers
  • Required impedance, such as 100Ω differential or 50Ω SE
A PCB with an FR4 substrate material

A PCB with an FR4 substrate material

PCB Layout

The board layout stage handles the primary design process because it includes the following steps.

Setting the Layer Stackup

As stated earlier, you might need assistance designing the stackup from your PCB manufacturer.

With this reference document, follow these guidelines to set up the stackup using the layer stackup manager design tool.

  • When creating a new board, the software automatically generates a single-layer stackup
  • Add a unique solder mask by clicking the “add layer” button (in most design applications)
  • Clicking “add stack” duplicates the selected stack, but you can change the title and properties of the new stack.
  • Also, you can alter the order of the stackup. And for flexible boards, enable the flex option.

Once complete, you should have a stackup of the board layers showing the following.

  • Layer name
  • Type (dielectric, signal, solder mask, etc.)
  • Material
  • Dielectric material
  • Layer thickness
  • Orientation
  • Dielectric constant

Set The PCB Design Rules

Design rules are instructions given to the board layout tool to help guide you as you design the board.

They fall into the following three broad categories.

  • Spacing design rules, such as between high and low voltage PCB traces, high and low-frequency signal lines, etc.
  • Physical design rules (differential pairs, via diameter, copper trace width, etc.)
  • Electrical design rules (frequency, impedance, and other electrical characteristics)

Once set, the software will ensure your PCB outline adheres to these rules as you outline the board.

Draw The Board Outline

The board outline is a closed contour of the PCB shape, and you can define it in either of these three ways.

  • Manual definition
  • From selected objects
  • From 3D body

The manual definition usually occurs by moving board vertices.

But use the second option if importing the outline as a DXF or DWG file from an MCAD tool.

However, if importing from a CAD tool, define the board outline from a 3D body.

An electrical engineer working on a PCB design

An electrical engineer working on a PCB design

Component Placement

The next step is to place the electronic components on the outline.

And a neat trick to use is to position these components on different board sections depending on the functionality.

For instance, group components that handle analog signals on one side.

And place digital signal components on the other end.

Perhaps the only thing they should share is the ground plane, which should sit between them.

The idea is to keep the signals from causing interference on traces carrying other types of electrical pulses.

Similarly, separate the high-speed/high-frequency signal components from the low-speed/low-frequency signal parts.

And in these separate areas, begin by placing the components at fixed locations on the design requirements.

Next, place the primary parts, like memory, CPU, etc., then position the auxiliary pieces to support the primary components.

They include decoupling capacitors, crystal oscillator clocks, resistors, etc.

A radial decoupling capacitor

A radial decoupling capacitor

Board Net Routing

If you recall, a net is the interconnection between two components.

So net-routing involves laying copper traces between parts or nodes.

You define these electrical paths using arcs, tracks, and vias (for multilayer boards).

The size of the copper traces and the spacing between them will follow the design rules set earlier.

And we recommend following this routing sequence.

  • Decoupling capacitor and via trace routing
  • Impedance, high-speed, and other critical signal trace routing
  • Non-critical routing

Complete the process by placing the ground and power plane electrical connections.

Do a Design Rule Check

Checking the design rules involves inspecting the physical and logical integrity of the board layout.

So you’ll compare the board design against the design rules to confirm whether the layout adheres to the clearance rules.

Complete Board Assembly/FAB Notes

The last step in the PCB layout process is to complete the assembly notes, which include the following.

  • PCB class
  • Silkscreen and solder mask color
  • Required IPC standards
  • Cut-out and stackup details
  • Drill chart/drill hole details
  • Board thickness
  • Number of layers
  • Impedance per layer
  • Version (number and date)

Generate Production Files

After creating the designs on your computer, generate the production files to send to your PCB manufacturer.

The typical one is the Gerber file, which includes the following.

  • Upper and lower copper layers
  • Top and bottom solder mask layers
  • Upper and lower solder paste layers
  • Top and bottom silkscreen layers
  • Interior signal, power, and ground layers

Also, generate these production files because they are critical for manufacturing.

  • Pick-and-place file
  • NC Drill file
  • ODB++ file
  • IPC 356 netlist file
  • Assembly drawings
  • Layout & schematic
An automatic pick-and-place machine (requires a pick-and-place file)

An automatic pick-and-place machine (requires a pick-and-place file)

Once you obtain these files, do a Design For Manufacturability check.

This check determines if any layout problems exist that can cause manufacturing issues.

Wrap-Up: Finalize Your Design and Get Your PCB Made

The PCB design process has multiple checks, but they are safety precautions to ensure the PCB layouts are error-free.

It is vital to eliminate issues at this stage because it is cheaper here than after manufacturing.

So follow the steps above, then send us the design files.

Or you can contact us if you need help with your circuit board design.

We’ll be happy to help.