PCB Design Glossary

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

A

• Annular Ring: The copper area that surrounds a drilled hole in a PCB. A sufficient annular ring width is essential to ensure a good connection when soldering components.
• Anti-Pad: An area where a pad or via has been removed from a plane layer. Anti-pads are used in designs to avoid short circuits or interference with other signals.
• Aperture: In photoplotting, the shape and size of the hole in a template through which light passes to draw an image on the resist-covered laminate. Apertures play a crucial role in defining accurate patterns for PCB designs.
• Array: A group of multiple identical circuits on a panel, often used for production efficiency. Using arrays can improve manufacturing throughput and reduce costs.
• Assembly: The process of mounting and soldering components onto a PCB. Proper assembly ensures the device functions correctly and can withstand regular usage.

B

• Backdrilling: The process of removing the unused portion of a plated through-hole to reduce signal distortion. Backdrilling is essential in high-speed designs to minimize signal reflection and improve performance.
• Blind Via: A via that connects an outer layer to an inner layer but doesn't pass through the entire board. Blind vias are used to save space and improve routing possibilities in multilayer PCBs.
• BOM (Bill of Materials): A list of components to be included on the PCB. The BOM ensures that all required components are available and accounted for during assembly.
• Buried Via: A via that connects two or more inner layers and doesn't have connections to an outer layer. Buried vias are used in complex multilayer designs where space is at a premium.

C

• CAD (Computer-Aided Design): Software tools used for designing PCBs. CAD tools enable designers to simulate and test their circuits before actual manufacturing.
• Conformal Coating: A protective coating applied to a PCB to prevent moisture and contaminant ingress. Conformal coatings are commonly used in environments where PCBs might be exposed to harsh conditions.
• Copper Pour: Filling an area on a PCB with copper, often connected to Ground or Power nets. Copper pours can enhance the electrical and thermal performance of the PCB.
• Copper Weight: The weight of copper used on the PCB, typically measured in ounces per square foot. Different copper weights are chosen based on the current carrying requirements of the circuit.
• Coverlay: A flexible film used to cover and protect the external circuits on a flex PCB. Coverlays are crucial for flex PCBs, offering protection without compromising flexibility.

D

• Daisy Chain: A wiring scheme where multiple devices are wired together in a sequence. This method is often used in bus architectures to connect multiple devices using a single communication line.
• Decoupling Capacitor: A capacitor used to filter noise from the power supply. Placing decoupling capacitors close to power pins on ICs helps maintain the stability of the power supply to the IC.
• Design For Manufacturing (DFM): Guidelines to ensure the PCB design can be easily and reliably manufactured. Adhering to DFM can reduce manufacturing costs and increase the yield of functional boards.
• Differential Pair: Two conductors (traces) used to transmit signals with an inverse relationship to reduce electromagnetic interference. Differential pairs are vital in high-speed designs to maintain signal integrity.
• DRC (Design Rule Check): Software-based checks run to ensure that the PCB layout meets specific fabrication and assembly requirements. Running a DRC helps identify potential issues before the PCB is manufactured.

E

• ECL (Emitter Coupled Logic): A type of digital circuitry used in high-speed applications. ECL is known for its fast switching times, making it suitable for certain high-frequency applications.
• Edge Connector: A connector on the edge of the PCB, often gold plated. Edge connectors are commonly used in cartridge-based video game systems and expansion cards.
• Electromagnetic Compatibility (EMC): The capability of a device to operate without causing or being affected by electromagnetic interference. EMC considerations are essential to ensure devices work harmoniously in shared environments.
• Electromagnetic Interference (EMI): Unwanted disturbances caused by electromagnetic radiation from an external source. EMI can affect the performance of electronic devices, causing disruptions or data loss. Shielding and proper design can help mitigate its effects.

F

• Fanout: The routing of traces from a component's pins to the outer layers, typically seen in BGAs. Proper fanout ensures efficient use of PCB real estate and optimized electrical performance.
• FPGA (Field-Programmable Gate Array): An integrated circuit that can be programmed by the user post-manufacturing. FPGAs are versatile, allowing for custom hardware designs and are widely used in diverse electronic applications.
• Ferrite Bead: A passive electronic component used to suppress high-frequency noise in electronic circuits. Ferrite beads act as a filter, ensuring cleaner power and signal lines.
• Fiducial: A round mark on the PCB used by assembly machines for alignment. These marks assist in precise component placement during the assembly process.
• Flex PCB (Flexible Printed Circuit Board): A PCB made of a flexible material, allowing it to bend. Flex PCBs are often chosen for devices requiring flexibility or limited space, such as in wearable electronics.
• Footprint: The layout of pads, holes, and spaces on the PCB where a component will be mounted. Correct footprints are vital for ensuring components fit and connect correctly during assembly.

G

• Gerber Files: Standard files used to control a photoplotter. They contain the information needed for PCB fabrication. Manufacturers rely on Gerber files to precisely reproduce a designer's intended layout.
• Ground Plane: A continuous block of copper on a PCB layer connected to the ground of the circuit. Ground planes aid in reducing noise and interference, promoting better circuit performance.

H

• HDI (High-Density Interconnect): PCB design techniques and technologies that use finer geometries and tighter component placement. HDI designs are essential for modern electronics, which require miniaturization while maintaining functionality.
• High-Frequency Design (HFD): In PCB design, it refers to circuits operating in the MHz to GHz range. HFD involves managing signal loss, electromagnetic interference, and impedance. It's essential for wireless and RF applications.
• High-Speed Design: PCB design techniques used to ensure signal integrity in fast circuits. As electronics evolve, the importance of high-speed design principles in ensuring reliable performance becomes paramount.

I

• Impedance: The resistance of a circuit to alternating current. Proper impedance matching is vital in certain designs, like RF circuits, to ensure maximum power transfer and reduced signal reflection.
• Integrated Circuit (IC): A compact assembly of electronic components, primarily transistors, on a single semiconductor substrate. ICs combine multiple circuit functions in one package, optimizing space and performance. Common in devices ranging from computers to mobile phones.
• Island: A small area of copper surrounded by a non-conductive material. It's essential to ensure that islands are properly connected or removed to prevent potential issues during operation.

J

• Jumper: A short wire or trace used to connect two points on a PCB. Jumpers provide a way to manually route or modify circuits, often for configuration or testing purposes.

K

• Keep-Out Area: An area where components or traces are not allowed due to mechanical or electrical constraints. This ensures safe distances from components that generate heat or require isolation.
• Kerning: The adjustment of spacing between characters in silkscreen labels. Proper kerning ensures the legibility and aesthetic appeal of text on the PCB.

L

• Laminate: The insulating material upon which the copper layer of a PCB is affixed. Laminates provide structural integrity and insulation, making them critical to PCB function and durability.
• Land: Another term for a pad on which a component is mounted. Ensuring proper land size is crucial for soldering and establishing reliable connections.
• Layer Stackup: The arrangement of insulating and conducting layers in a multilayer PCB. The layer stackup determines many of the board's electrical properties and can affect signal integrity and performance.

M

• Mask: A material applied to prevent solder or plating in certain areas. Common types include solder mask and peelable mask. Masks help ensure that soldering happens only where it's needed and protect areas of the board from oxidation or contamination.
• Microvia: A small via with a diameter of less than 0.15mm, often used in HDI designs. Microvias cater to miniaturization trends in electronics, allowing for denser component arrangements on the board.

N

• Netlist: A list of connections between components in a PCB design. The netlist acts as a blueprint, guiding the routing process and ensuring components are properly interconnected.
• Node: Any single-point connection of two or more circuit elements. Nodes are crucial for understanding electrical flow and connectivity within a circuit.

O

• Ohm: The unit of electrical resistance. Understanding the ohmic values in a circuit helps designers ensure components are correctly rated and will operate safely.

P

• Pad: A portion of exposed metal on the surface of the board to which a component is soldered. Pads act as anchors and electrical contacts for components, making them critical for proper PCB function.
• Panel: A larger board containing multiple smaller boards (PCBs) that will be separated after manufacturing. Using panels is a manufacturing efficiency, allowing multiple boards to be produced at once.
• PCB (Printed Circuit Board): The board base for physically supporting and wiring surface-mounted and socketed components in most electronics. PCBs form the backbone of almost every electronic device in use today.
• Plated Through Hole (PTH): A hole in a PCB where the walls of the hole are plated with copper, connecting traces from one layer of the board to another. PTHs provide vertical connectivity in multi-layer boards.
• Polygon Pour: A defined shape on a PCB layer where copper is poured to create a continuous connection. It's commonly used to create ground or power regions on a PCB.

Q

• QFN (Quad Flat No-lead): A flat package type with no component leads. QFNs are compact packages, often chosen for space-constrained designs.

R

• Ratsnest: A tangled, un-routed web of airwire connections showing where connections are required. The ratsnest aids designers in visualizing the remaining connections during PCB layout.
• Reference Designator: An alphanumeric code (like R1, C2) used to identify components on a PCB. These designators provide a map for assembly and troubleshooting.
• Routing: The process of connecting various components on a PCB using traces. Proper routing is essential for signal integrity and overall board functionality.

S

• Schematic: A diagram that represents the elements of a system and their connections. Schematics serve as blueprints for PCB design, detailing the logical connections between components.
• Serpentine: A design pattern of a trace that snakes back and forth to achieve delay or length matching. This is especially crucial in high-speed designs where timing between signals is vital.
• Signal Integrity (SI): The quality of an electrical signal's waveform in PCB design. SI ensures signals transfer without distortion or interference. It's vital for high-speed circuits, influenced by trace lengths, impedance, and crosstalk. Proper design helps optimize SI.
• Silkscreen: The layer on a PCB that contains component designators, test points, logos, and other markings. This layer provides visual guidance for PCB assembly and troubleshooting.
• SMD (Surface Mount Device): A component that is mounted directly to the surface of the PCB. SMDs have enabled miniaturization in electronics, leading to more compact and efficient designs.
• Solder Bridge: An unintended connection of solder between conductors. Such bridges can cause short circuits and need to be avoided or corrected during the soldering process.
• Star Ground: A grounding method that connects individual grounds to a single central point. This technique can help reduce noise and interference in a circuit.
• Stitching Via: A via used to connect two ground planes to reduce electromagnetic interference. These vias can help in maintaining signal integrity across the PCB.

T

• Teardrop: A filleted area added where a trace connects to a pad or via, improving strength and reliability. Teardrops help reduce stress points that can lead to potential fractures in the copper.
• Test Point: A location on a PCB where a probe can be connected for testing. Test points facilitate easier troubleshooting and validation of the board's functionality.
• Thermal Analysis: A technique that studies material properties as they change with temperature. In PCB design, it assesses heat distribution, ensuring components stay within safe temperature ranges and maintain reliable performance.
• Thermal Pad: A pad designed to enhance heat dissipation from a component to the PCB. Efficient heat management can extend the lifespan of electronic components and the board itself.
• Thermal Relief: A pattern that allows a pad to be soldered without transferring heat away too quickly. This ensures that solder joints form correctly without premature cooling.
• Tombstoning: A defect where a surface-mount component stands up vertically during soldering. This can lead to non-functional connections and requires rework.
• Trace: A continuous path of copper on a PCB layer that forms the circuit connections. Traces are the highways of a PCB, directing current where it's needed.
• Twist & Flat: A method of pairing conductors for balanced signal routing. It can be beneficial in designs where differential signaling or noise reduction is crucial.

U

• UL (Underwriters Laboratories): An organization that sets safety standards for electronic components and products. Achieving UL certification can provide assurances of a product's safety and quality.

V

• Via: A plated through-hole used to route a trace from one layer of the board to another without attaching to a component lead or pad. Vias are integral to multilayer PCB designs, allowing for complex routing without overcrowding a single layer.
• V-Scoring: A groove cut on the panel to assist in breaking apart individual PCBs. This method is commonly used in mass production to efficiently separate multiple boards from a larger panel.

W

• Wave Soldering: A process in which the bottom side of a PCB is passed over a molten wave of solder to solder the component leads to the board. It's a time-tested method for efficiently soldering through-hole components in bulk.

Z

• ZIF (Zero Insertion Force) Connector: A connector designed to allow the insertion of a component without any force. ZIF connectors ensure minimal wear and stress on both the connector and component, making them ideal for applications that require frequent insertions and removals.

Conclusion

Navigating the world of printed circuit boards (PCBs) can initially seem daunting due to the array of specific terminologies. We hope this glossary serves as a valuable tool in clarifying and demystifying many of these terms for both beginners and those looking to brush up on their PCB vocabulary. The world of electronics and PCB design is vast and ever-evolving. As you continue your journey, remember that understanding the terminology is a foundational step to mastering the field. For those seeking to delve further into PCB design and application, we recommend exploring advanced topics and resources. With continuous learning and application, the intricate landscape of PCBs will soon become familiar territory.