How to Use a Right-Angle BNC Connector in KiCad: Designing a PCB that uses coaxial connectors like BNC can be challenging, especially when space is tight. Right-angle BNC connectors offer a space-efficient solution that allows horizontal cable entry, making them ideal for compact layouts and front-panel access. If you’re using KiCad for your design, there are specific steps and best practices to follow to integrate right-angle BNC connectors correctly and reliably.
In this guide, we’ll walk you through everything you need to know about right-angle BNC connectors in KiCad—from selection and footprint creation to placement, routing, and final checks.
Understanding Right-Angle BNC Connectors in PCB Design
BNC (Bayonet Neill–Concelman) connectors are a type of coaxial RF connector commonly used in test equipment, radio, and video systems. A right-angle BNC connector bends the connector 90 degrees from the PCB, allowing the cable to exit parallel to the board rather than vertically. This form factor is especially useful in space-constrained enclosures or edge-mounted applications.
When designing a PCB that uses right-angle BNC connectors, mechanical alignment and signal integrity must be considered. Right-angle versions typically have through-hole pins, so they require precision in both the schematic and footprint to ensure correct placement.
Choosing the Right BNC Connector for Your KiCad Project
Choosing the correct right-angle BNC connector is crucial, as not all connectors will suit your electrical or mechanical requirements.
BNC Connector Types and Orientation
Right-angle BNC connectors are available in multiple mounting styles: through-hole, panel-mount, and sometimes hybrid models with grounding tabs. When selecting one, consider:
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Impedance: 50Ω or 75Ω depending on signal type
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Mounting type: Through-hole is most common for PCB mounting
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Termination style: Solder pins vs. press-fit
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Panel alignment: Will the connector sit flush with the edge of the board?
Key Electrical and Mechanical Specifications
BNC connectors must match your application’s voltage and frequency requirements. Key parameters include:
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Voltage rating
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Operating frequency (MHz or GHz)
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Dielectric material (for signal integrity)
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Environmental tolerance (e.g., for outdoor applications)
Compatibility with KiCad Libraries
KiCad’s official library may not include the exact BNC connector you need. You can:
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Search third-party libraries (SnapEDA, UltraLibrarian, SamacSys)
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Import from the manufacturer’s site (some provide KiCad symbols/footprints)
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Design your own footprint using KiCad’s footprint editor (recommended if exact specs are needed)
Importing or Creating a Right-Angle BNC Footprint
Once you’ve selected your part, it’s time to get or create a footprint.
Using Pre-Made Footprints from Library Repositories
Websites like SnapEDA, UltraLibrarian, and Mouser often provide KiCad-compatible footprints. Simply download the .kicad_mod file and import it into your project’s custom library.
Steps:
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Download the footprint (and symbol if available).
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Open Footprint Editor in KiCad.
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Create or open a custom library, and import the file.
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Associate the footprint with your symbol in the schematic.
Manually Designing a Footprint in Footprint Editor
If a pre-made version isn’t available, create the footprint manually:
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Gather the mechanical drawing (datasheet) of the connector.
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In Footprint Editor, define pad locations and hole sizes.
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Add mounting holes if needed.
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Define the outline and silkscreen on the
F.SilkSandF.Fablayers. -
Ensure correct pin numbering (usually center pin = signal, side pins = ground).
Tips for Mechanical Accuracy and Mounting Holes
Make sure to:
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Place the connector close to or exactly at the board edge.
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Use the Edge.Cuts layer to define where the board ends.
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Align mounting holes and verify with a 3D model if available.
Integrating the Connector into Your Schematic and PCB Layout
Once the footprint is ready, you’ll move to schematic capture and layout.
Adding the Symbol in Schematic Editor
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Insert the BNC connector symbol into the schematic.
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Label the pins clearly (e.g.,
RF_IN,GND). -
Connect the center pin to your signal net and outer pins to ground.
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Run ERC (Electrical Rule Check) to confirm no unconnected pins.
Routing Traces and Ensuring Signal Integrity
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Use short, direct traces to avoid signal degradation.
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Maintain controlled impedance if dealing with RF signals.
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Use ground planes and via stitching to reduce EMI and reflections.
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Avoid 90-degree bends in trace routing—use two 45-degree angles instead.
Verifying Mechanical Placement on the PCB Edge
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Place the connector near the board edge or enclosure opening.
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Use the 3D Viewer (
Alt+3) to ensure alignment and fit. -
Leave adequate clearance for the BNC bayonet twist-lock mechanism.
Final Checks and Exporting for Manufacturing
Once layout and routing are complete, perform final checks before sending your files to a manufacturer.
Design Rule Check (DRC) and Electrical Rule Check (ERC)
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Run DRC to ensure spacing, pad size, and track width are acceptable.
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Check for unconnected nets, short circuits, or silkscreen over holes.
Generating 3D Models for Verification
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Use KiCad’s 3D Viewer to verify mechanical fit.
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Add a 3D model of the BNC connector if available (STEP files can be imported).
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Confirm edge clearance and mounting hole alignment.
Exporting Gerbers and BOM
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Export your Gerber files, drill files, and Pick and Place if needed.
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Generate a Bill of Materials (BOM) that includes the correct BNC connector part number.
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Double-check component references, footprints, and orientation.
Conclusion
Working with right-angle BNC connectors in KiCad involves more than just placing a symbol on the schematic. You need to consider mechanical dimensions, signal integrity, footprint accuracy, and board layout constraints. Whether you’re designing RF circuits, video equipment, or test gear, proper integration of a right-angle BNC can significantly improve usability and reliability.
By following the steps above—choosing the right part, ensuring footprint accuracy, and double-checking mechanical placement—you’ll be well on your way to a robust and professional PCB design.
