A brief understanding of PCB layout
Referencing bits are assigned to components when they are placed on a PCB or schematic. This code is an alphanumeric abbreviation that represents a particular component. It helps the design team communicate this component to team members and between internal documents and printed circuit design software.
With the right design software, you can place and edit reference bit numbers throughout your design document. This includes the PCB layout, component data, and schematic. You can edit and place reference bit numbers throughout your design documents, such as the PCB layout and component data. PCB design software will also allow you to stay in sync with the placement and modification of the PCB reference bit number. What do you use to refer to symbols, materials, or the layout of your project parts?
Schematics, board layouts and bill of materials all require components.
Other design documents may have a reference bit number. Your ECAD software will assign the reference bit displayed on the PCB to the component specified in the design document. Alternatively, the user can customize it to suit the format needed for the project.
When using printed circuit project files, it is easy to lose track of your schematic, PCB layout and bill of materials. When working with printed-circuit project files, it is possible for your schematic, PCB design, bill of material, and final manufacturing output to become out of synchronization. Altium Designer can help you synchronize your PCB reference bits throughout your schematic and schematic diagrams and PCB layout.
What is a reference bit number?
All PCB reference bit numbers appear on the PCB surface layer on top of the silkscreen layer (top and bottom overlays). The reference bit number of a component is a combination of letters and numbers that are assigned to the component. Reference bit numbers for each component are unique, so they will never be repeated. You can find the reference bit number for specific components when you create a design database. This includes the schematic design document (SDD), PCB layout, and bill of material.
The importance of reference bit number in PCB layout
The Gerber file containing the silkscreen layer will include the PCB bit number for every component. The silkscreen layer with the reference bit number, and any other markings will be screen printed onto the PCB solder mask as part of the final production step.
Reference bit numbers are useful for many tasks besides schematic design and component placement in PCB layout. Reference bit numbers are useful for manual assembly, manual inspection, testing, and debugging procedures. PCB reference numbers also allow designers to quickly identify the components on a PCB without looking at the BOM. The standardization of the reference bit numbers on electrical drawings, and in ECAD programs such as Altium Designer makes it obvious to designers.
Common PCB Reference Bit Numbers
Two standards specify the format of the reference bit numbers for 45 electronic components that appear in electrical diagrams, including schematics and corresponding printed circuit layouts. These are the IEEE 315-1975 and ASME Y14.44-2008 standards. These standards specify the letter prefix used in a PCB layout for a given component type.
Lists of common PCB reference bit number prefixes used in circuit board design software:
- U: Integrated Circuit
- D, CR: diode reference bit number
- C: Capacitor
- R: Resistor
- L: Sensor
- J: Connector
- F: Fuse
- Y: Crystal Oscillator
- Q: Discrete Transistor
The polarity indicator can be placed in a PCB layout near the diode bit number for a clear distinction between cathode and anode. It is important to note that polarized capacitances use “+” (or a dot) as a positive terminal. To indicate the orientation of a component, it is common to use a diode icon near the diode bit number. The same strategy is used with transistors to make the orientation of the components clear for the assembler.
Define PCB reference bit number prefixes
Referencing bits will be numbered sequentially to identify specific components on the schematic, in the bill of materials, and in the PCB layout. You can create PCB packages and schematic symbols for components, and then build your project library. This will allow you to define prefixes for PCB reference bit numbers for custom or specialized parts. You can place the reference number anywhere around the component.
- Altium Designer’s CAD tools allow you to create PCBs with standard reference bits.
- Your design documents and output will be consistent with PCB bit numbers if you use the best ECAD software.
- Altium Designer’s Manufacturer Part Search allows you to search for standard components within your PCB supply chain. This application helps you access PCB packages with the correct pinouts and connection graphics, as well as reference bit numbers.
Synchronize PCB reference bit numbers
It is important to ensure that the reference bit numbers are synchronized across your PCB design and schematic. When generating your bill-of-materials, your program should also extract the data for your supplier, your part number, and your reference bit numbers directly from your schematic and PCB layout. This information does not need to be manually entered into the manufacturer table. You can synchronize your design documents with the manufacturing output using a CAD tool instead of manually doing it.
Altium Designer synchronizes all design documents and BOMs
The ActiveBOM application and the integrated schematic editor in Altium Designer are key tools to keep your designs synchronized. These features are included in Altium Designer along with the PCB editor, and the integrated design rules engine automatically checks for synchronization errors as you build your board.
Altium Designer synchronization features
Altium Designer also allows you to update your design documentation automatically. This will help you to stay productive. As you design, easily set up reference bit numbers. You can also apply updates to components. No other program allows you to maintain your design database in sync so easily.
- Altium Designer allows you to automatically place any part, from mechanical to electrical, in your Bill of Materials. It can be added to the BOM table if it’s defined in the schematic as a component.
- Altium Designer keeps you productive with its PCB Reference bit number Annotation, which iterates your reference bits as you work on the schematic editor or PCB layout.
- Altium Designer allows ECAD designers to get a 3D view of a board in order to evaluate assembly and bit number arrangements.
Generate manufacturing results with complete reference bit numbers
Altium Designer allows you to quickly create all the files your manufacturer requires. OutJob files capture your PCB component and layout data instantly and create the standard deliverables that manufacturers and assemblers require. Deliverables created in Altium Designer include PCB bit numbers, component procurement data, and assembly information. This helps to ensure accuracy and assists with debugging and inspection after manufacturing.
Altium Rules-Driven Design Software: Maintaining Productivity and Efficientness in the Design Process
Altium Designer’s complete set of board design tools works together to keep you productive and efficient. The application’s powerful, rule-driven design engines allow the documentation feature to take data directly from the PCB layout.
Altium Designer software rules
- Altium Designer provides you with everything you need to prepare board layout documentation and create design data. Altium provides the best PCB design tools to help you stay on the cutting edge of new technology.
- Defining reference bit symbols begins with schematic input. Altium Designer’s schematic entry environment is the best in the industry. It provides access to component, library, and supply chain information.
- Altium 365 is the only cloud-based platform in the industry that allows users to share their data with their manufacturing partners.
Altium Designer’s full set of tools for component creation and management will help you create the most accurate database possible to support your PCB designs. Use the best ECAD software in the industry to design PCBs and prepare output for manufacturing.
