Common mistakes in PCB board schematic diagrams:
(1) The ERC pin has no access signal:
a. Ensure I/O attributes are defined for the pins when the package is created;
b. Modify inconsistent grid properties when creating components or placing components and connect the pins and lines accordingly;
c. Ensure the pin direction is correct when creating a component and connect it to the non-pin name end.
(2) The component exceeds the drawing bounds: Ensure the component is created in the center of the drawing paper in the component library.
(3) The project file netlist can only be partially transferred to the PCB board: Select global when generating the netlist.
(4) Avoid using annotate with self-created multi-part components.
Common mistakes in PCB board:
(1) NODE is not found when the network is loaded:
a. The components in the schematic diagram use packages that are not in the PCB library;
b. The components in the schematic diagram use packages with inconsistent names in the PCB library;
c. The components in the schematic diagram use packages with inconsistent pin numbers in the PCB library. For example, a triode may have pin numbers labeled as e,b,c in the schematic but 1, 2, 3 in the PCB board.
(2) When printing, it cannot always be printed on one page:
a. It is not at the origin when creating the PCB library;
b. The component has been moved and rotated many times, resulting in hidden characters outside the PCB board boundary. To resolve this, select to show all hidden characters, shrink the PCB board, and move the characters within the boundaries.
(3) The DRC network is divided into several parts:
This indicates that the network is not connected. To resolve this issue, examine the file and use CONNECTED COPPER to locate the disconnected part.
In PCB board design, wiring is a crucial step in completing product design. The entire PCB board’s wiring design process is limited; the skills required are fine and the workload is substantial. PCB board wiring includes single-sided, double-sided, and multi-layer wiring, as well as automatic and interactive routing. Prior to automatic routing, interactive pre-routing can be used for lines with stricter requirements. The input and output ends should avoid being adjacent and parallel to prevent reflection interference. Ground wire isolation should be added if necessary, and wiring on two adjacent layers should be perpendicular to each other to prevent parasitic coupling. The routing rate of automatic routing depends on good layout, and routing rules can be preset, including the number of bends, vias, steps, etc. Initially, exploratory wiring should connect short wires quickly, followed by labyrinth routing, with re-wiring as needed to improve the overall effect.
Handling of power and ground wires:
Even if the PCB board wiring is well completed, interference caused by inadequate consideration of power supply and ground wires can reduce product performance and success rate. Proper wiring of power and ground wires is essential to minimize noise interference and ensure product quality.
Common ground processing of digital circuits and analog circuits:
With many PCB boards consisting of a mix of digital and analog circuits, it’s crucial to consider mutual interference, especially noise on the ground wire. Digital and analog grounds should be separated within the board but connected at the interface with the outside world. Signal lines should be kept away from sensitive analog devices, and different grounds on the PCB board should be established based on system design.
Signal lines are routed on the electrical (ground) layer:
In multi-layer printed board wiring, considering routing on the electrical (ground) layer can optimize board space and reduce production costs. Maintaining the integrity of the power and ground planes is essential.
Handling of connecting legs in large area conductors:
When connecting components in large grounding areas, thermal pads can help reduce the risk of virtual solder joints caused by excessive heat dissipation during welding. This approach should also be applied to ground legs on multilayer PCB boards for optimal electrical performance and manufacturing processes.
(1) The ERC pin has no access signal:
a. Ensure I/O attributes are defined for the pins when the package is created;
b. Modify inconsistent grid properties when creating components or placing components and connect the pins and lines accordingly;
c. Ensure the pin direction is correct when creating a component and connect it to the non-pin name end.
(2) The component exceeds the drawing bounds: Ensure the component is created in the center of the drawing paper in the component library.
(3) The project file netlist can only be partially transferred to the PCB board: Select global when generating the netlist.
(4) Avoid using annotate with self-created multi-part components.
Common mistakes in PCB board:
(1) NODE is not found when the network is loaded:
a. The components in the schematic diagram use packages that are not in the PCB library;
b. The components in the schematic diagram use packages with inconsistent names in the PCB library;
c. The components in the schematic diagram use packages with inconsistent pin numbers in the PCB library. For example, a triode may have pin numbers labeled as e,b,c in the schematic but 1, 2, 3 in the PCB board.
(2) When printing, it cannot always be printed on one page:
a. It is not at the origin when creating the PCB library;
b. The component has been moved and rotated many times, resulting in hidden characters outside the PCB board boundary. To resolve this, select to show all hidden characters, shrink the PCB board, and move the characters within the boundaries.
(3) The DRC network is divided into several parts:
This indicates that the network is not connected. To resolve this issue, examine the file and use CONNECTED COPPER to locate the disconnected part.
In PCB board design, wiring is a crucial step in completing product design. The entire PCB board’s wiring design process is limited; the skills required are fine and the workload is substantial. PCB board wiring includes single-sided, double-sided, and multi-layer wiring, as well as automatic and interactive routing. Prior to automatic routing, interactive pre-routing can be used for lines with stricter requirements. The input and output ends should avoid being adjacent and parallel to prevent reflection interference. Ground wire isolation should be added if necessary, and wiring on two adjacent layers should be perpendicular to each other to prevent parasitic coupling. The routing rate of automatic routing depends on good layout, and routing rules can be preset, including the number of bends, vias, steps, etc. Initially, exploratory wiring should connect short wires quickly, followed by labyrinth routing, with re-wiring as needed to improve the overall effect.
Handling of power and ground wires:
Even if the PCB board wiring is well completed, interference caused by inadequate consideration of power supply and ground wires can reduce product performance and success rate. Proper wiring of power and ground wires is essential to minimize noise interference and ensure product quality.
Common ground processing of digital circuits and analog circuits:
With many PCB boards consisting of a mix of digital and analog circuits, it’s crucial to consider mutual interference, especially noise on the ground wire. Digital and analog grounds should be separated within the board but connected at the interface with the outside world. Signal lines should be kept away from sensitive analog devices, and different grounds on the PCB board should be established based on system design.
Signal lines are routed on the electrical (ground) layer:
In multi-layer printed board wiring, considering routing on the electrical (ground) layer can optimize board space and reduce production costs. Maintaining the integrity of the power and ground planes is essential.
Handling of connecting legs in large area conductors:
When connecting components in large grounding areas, thermal pads can help reduce the risk of virtual solder joints caused by excessive heat dissipation during welding. This approach should also be applied to ground legs on multilayer PCB boards for optimal electrical performance and manufacturing processes.
