Protel PCB: A Practical Guide for Beginners

What Protel Is

Protel is a family of printed circuit board design tools that originated in Australia in the late 1980s and grew into one of the most widely used packages in the industry. For a generation of engineers, learning PCB design meant learning Protel, and the name is still used for the workflow even by people running its successor.

The lineage matters because licences, file formats and habits are still tied to it. The line ran from the DOS versions through Protel 98, 99 and 99SE, then to Protel DXP and DXP 2004. After that the product was renamed Altium Designer, and Altium Designer is what the same codebase is called today. A design started in Protel 99SE can still be imported into a current Altium installation, which is why old projects survive.

The Two Halves of the Tool

Every PCB package, Protel included, has two connected halves. The schematic editor captures the circuit as symbols and connections and produces a netlist. The board editor takes that netlist, the footprints and the mechanical outline, and turns them into copper, mask, legend and drill data.

Schematic capture. Symbols are placed, wired and annotated. The annotation assigns a designator to each part, and it is done before the board is laid out because the board inherits the designators. A design rule check in the schematic catches unconnected pins, duplicated designators and single ended nets before any layout work begins.

Footprint libraries. Every symbol has to be matched to a footprint that describes the physical pads. Most design errors in a first board come from this step rather than from the circuit, so the footprint is checked against the manufacturer drawing before it is used.

Board layout. Components are placed, the outline and the mounting holes are defined, the board is divided into keep-out regions, and the connections are routed on the available layers.

Design rule check. The rules define the minimum trace width, the minimum clearance, the minimum annular ring, the hole sizes and the mask expansion. The checker reports violations, and a clean check is the gate before output. Our notes on PCB design and layout cover the rules themselves.

The Workflow, Step by Step

1. Create the project and the schematic document, and set the units and the grid.
2. Draw the circuit, including the power and ground connections, and annotate it so every component has a unique designator.
3. Run the electrical rule check and resolve every warning that indicates a real connection problem.
4. Assign a footprint to every symbol from a library, checking each against the component datasheet.
5. Create the board document and import the netlist, which places every component in a cluster outside the outline.
6. Draw the board outline on the mechanical layer and place the mounting holes and the connectors, since those are fixed by the enclosure.
7. Place the remaining components in functional blocks, keeping the critical nets short and the noisy circuits separated from the sensitive ones.
8. Set the design rules for the fabricator capability, then route, using a ground plane or a large ground pour on at least one layer.
9. Run the design rule check, fix the violations, and add the copper pour and its stitching vias.
10. Run the final check, then generate the Gerber files, the drill file and the assembly drawings, and verify them in a viewer before sending them out.

Output and Verification

The fabrication output is a set of Gerber files, one per layer, plus the drill file and a drawing that states the stack, the finish and the tolerances. The single most useful habit in the whole workflow is to open the Gerber set in a viewer and look at it as a fabricator would, layer by layer, before the order is placed. Errors that are invisible in the design tool, such as a mask opening that is too small or a silkscreen line printed over a pad, are obvious in the viewer.

Two checks are worth running every time. Confirm that the drill file and the copper layers agree, since a hole with no pad and a pad with no hole are both defects. And confirm that the paste and mask layers match the pads, because a mask opening that is too small produces a solder bridge. Our notes on PCB manufacturing describe what the fabricator does with the data and where a badly prepared file causes trouble, and our notes on prototype PCB assembly describe how to use the first board to prove the design.

Working with Old Protel Files

Legacy designs arrive in several formats, and the route to reuse them is usually to import them into a modern tool rather than to keep an old installation running. The importers handle the common Protel formats, and the main issues are the footprint libraries, which often resolve to different names, and the design rules, which do not translate exactly and have to be re-entered for the current fabricator capability.

Where a board is being reissued rather than redesigned, the useful practice is to import the design, generate the Gerber set, and compare it layer by layer against the Gerber set from the original board. That catches any geometry that changed during the import, and it is far cheaper than discovering it on a panel.

When to Move to a Modern Tool

Protel and its descendants remain capable of designing anything from a two layer board to a high density interconnect stack, and there is no technical reason to abandon a working installation. The reasons to migrate are practical: current tool versions receive the library updates and the fabrication output formats that a modern fabricator expects, the design rule system is more expressive, the differential pair and length matching tools are far better for high speed work, and support and training are available.

For a beginner, the more useful question is not which package but which set of habits. A designer who sets the design rules from the fabricator capability, checks every footprint against a datasheet, keeps a continuous ground plane, and reviews the Gerber output before ordering will produce a working board in any of these tools. Our notes on quality management describe the controls that catch what the design tool cannot, and our notes on PCB assembly describe the build that follows.

Common Beginner Mistakes

• Footprint errors. The footprint is designed from memory rather than from the drawing, and the pads do not match the part.
• Design rules left at the default. The default clearance is finer than the chosen fabricator can produce, and the board is quoted at a higher price or rejected.
• No ground plane. A two layer board with no ground pour on either side has no defined return path and radiates.
• Silkscreen over pads. The legend is printed over a solderable area, which the assembly house will have to remove by hand.
• Test access forgotten. There are no test points, so a board that fails is impossible to debug without a probe on a component pad.
• Gerber files not checked. The most expensive mistake, and the easiest to avoid with a free viewer.

FAQ

Is Protel still available? The product line continues as Altium Designer. Older Protel versions are no longer maintained, and legacy files are usually imported into a current tool.

Can I design a professional board in Protel? Yes. The tool is capable of multilayer and fine geometry work; the limitation is the age of the libraries and the output support, not the routing engine.

What files does a fabricator need? A Gerber file for each layer, a drill file, and a drawing or note that specifies the stack, the copper weight, the finish, the board thickness and the tolerances.

What is the most common cause of a scrapped first board? A footprint that does not match the component, followed by design rules set finer than the fabricator can hold.

Conclusion

Protel is the ancestor of Altium Designer and still the mental model many engineers use for PCB design. The workflow has not changed: capture the schematic, assign footprints from the drawings, set the rules from the fabricator capability, route with a continuous ground, run the checks, and review the Gerber output in a viewer before ordering. The tool is only a part of that, and the habits are what make the board work.