**Common Mistakes in Schematic and PCB Diagrams**
1. Common errors in schematic diagrams:
(1) Signal connections missing from the ERC report pin:
a. I/O attributes for the pins are defined during package creation;
b. Inconsistent grid settings may be altered when components are created or placed, leading to unconnected pins and wires;
c. During component creation, pin directions may be reversed, resulting in unconnected ends that should be linked.
(2) Components extending beyond the drawing boundary: this often occurs when components are not centered properly on the diagram paper within the component library.
(3) The netlist of the created project file can only be partially imported into the PCB: this happens when the global option is not selected during netlist generation.
1. When using multi-part components created by yourself, avoid using the annotate function.
2. Common errors in PCB design:
(1) Error reported: NODE not found when loading the network:
a. Components in the schematic use packages not present in the PCB library;
b. Components in the schematic use packages with mismatched names in the PCB library;
c. Components in the schematic use packages with mismatched pin numbers compared to the PCB library. For example, a transistor may have pin numbers as e, b, c in the schematic but as 1, 2, 3 in the PCB.
(2) Difficulty in printing the design on a single page:
a. The design origin was not set correctly when creating the PCB library;
b. The component has been moved and rotated multiple times, leading to hidden elements outside the PCB board boundary. To resolve this, show all hidden elements, resize the PCB, and then reposition the elements within the boundary.
(3) DRC reporting network divided into multiple sections:
Indicates that the network is not fully connected. Refer to the report file and use the CONNECTED COPPER tool to locate the issues.
3. Additional tips:
– Use Windows 2000 as much as possible to reduce the risk of blue screens.
– Export the file multiple times to create a new DDB file, which helps reduce file size and minimizes the chance of PROTEL freezing.
– For more complex designs, avoid relying solely on automatic routing.
4. PCB routing is a crucial step in completing the product design. It encompasses single-sided, double-sided, and multilayer routing, and involves both automatic and interactive routing methods. Interactive routing can be used for pre-wiring critical lines before automatic routing is applied. Ensure that input and output ends are neither adjacent nor parallel to prevent reflection interference. Use ground wires for isolation if necessary, and ensure that the routing of adjacent layers is perpendicular to each other to minimize parasitic coupling.
5. The efficiency of automatic routing depends heavily on a well-organized layout. Routing rules should be preset, including the number of bends, vias, and steps. Typically, start with the most convoluted routes, quickly connect short wires, and then proceed with more intricate routing. Optimize the global routing path, disconnect laid wires as needed, and re-route to enhance overall performance.
6. In high-density PCB designs, through-holes are often deemed inefficient as they occupy valuable routing channels. To address this, blind and buried-hole technologies have been developed. These technologies not only replace through-holes but also conserve routing channels, making the design process more efficient and comprehensive.
7. PCB design is both complex and straightforward. Mastery requires extensive experience and practice by electronic engineering designers. True understanding comes from hands-on experience in the field.
1. Common errors in schematic diagrams:
(1) Signal connections missing from the ERC report pin:
a. I/O attributes for the pins are defined during package creation;
b. Inconsistent grid settings may be altered when components are created or placed, leading to unconnected pins and wires;
c. During component creation, pin directions may be reversed, resulting in unconnected ends that should be linked.
(2) Components extending beyond the drawing boundary: this often occurs when components are not centered properly on the diagram paper within the component library.
(3) The netlist of the created project file can only be partially imported into the PCB: this happens when the global option is not selected during netlist generation.
1. When using multi-part components created by yourself, avoid using the annotate function.
2. Common errors in PCB design:
(1) Error reported: NODE not found when loading the network:
a. Components in the schematic use packages not present in the PCB library;
b. Components in the schematic use packages with mismatched names in the PCB library;
c. Components in the schematic use packages with mismatched pin numbers compared to the PCB library. For example, a transistor may have pin numbers as e, b, c in the schematic but as 1, 2, 3 in the PCB.
(2) Difficulty in printing the design on a single page:
a. The design origin was not set correctly when creating the PCB library;
b. The component has been moved and rotated multiple times, leading to hidden elements outside the PCB board boundary. To resolve this, show all hidden elements, resize the PCB, and then reposition the elements within the boundary.
(3) DRC reporting network divided into multiple sections:
Indicates that the network is not fully connected. Refer to the report file and use the CONNECTED COPPER tool to locate the issues.
3. Additional tips:
– Use Windows 2000 as much as possible to reduce the risk of blue screens.
– Export the file multiple times to create a new DDB file, which helps reduce file size and minimizes the chance of PROTEL freezing.
– For more complex designs, avoid relying solely on automatic routing.
4. PCB routing is a crucial step in completing the product design. It encompasses single-sided, double-sided, and multilayer routing, and involves both automatic and interactive routing methods. Interactive routing can be used for pre-wiring critical lines before automatic routing is applied. Ensure that input and output ends are neither adjacent nor parallel to prevent reflection interference. Use ground wires for isolation if necessary, and ensure that the routing of adjacent layers is perpendicular to each other to minimize parasitic coupling.
5. The efficiency of automatic routing depends heavily on a well-organized layout. Routing rules should be preset, including the number of bends, vias, and steps. Typically, start with the most convoluted routes, quickly connect short wires, and then proceed with more intricate routing. Optimize the global routing path, disconnect laid wires as needed, and re-route to enhance overall performance.
6. In high-density PCB designs, through-holes are often deemed inefficient as they occupy valuable routing channels. To address this, blind and buried-hole technologies have been developed. These technologies not only replace through-holes but also conserve routing channels, making the design process more efficient and comprehensive.
7. PCB design is both complex and straightforward. Mastery requires extensive experience and practice by electronic engineering designers. True understanding comes from hands-on experience in the field.
