Introduction to the Self-Inspection Process of PCB Design
1. **Structural Design**
1) Verify the PCB floor plan and the printed structure diagram;
2) Check the location and diameter of the mounting holes;
3) Inspect the wiring constraint areas.
2. **Component Library**
1) Confirm the component sizes;
2) Ensure the BGA device’s silk screen frame strictly matches the size specified in the DATA SHEET;
3) Verify that the pin count of the component matches the definition in the DATA SHEET;
4) Check the MALE/FEMALE (male and female) designation;
5) Compare the transistor pins with the DATA SHEET;
6) Ensure the first pin of the IC or multi-pin connector is represented by a square pad;
7) The silkscreen logo for polar components should be clear;
8) Verify the position and diameter of the component positioning holes.
**3. Component Layout**
1) The components must not overlap.
2) The spacing between components should not be less than 8 mils.
3) Ensure that components comply with the restrictions defined in the no-go zones.
4) Structural part screws should not contact any traces.
5) Decoupling capacitors should be placed near the relevant components.
6) A 1mm or 1.5mm MARK point should be placed at the diagonal corners of the PCB.
**4. PCB Routing**
1) Verify that routing complies with the no-go area requirements.
2) Routing on adjacent layers should be perpendicular to each other.
3) Critical signal traces should be individually inspected.
4) Ensure that differential signal traces are routed in parallel and have equal lengths.
5) The power trace capacity should be checked.
6) Sampling resistors must be routed separately to the sampling points.
7) Remove any unused copper areas when applying copper fills.
**5. Solder Mask**
1) The solder mask window should be 2 mils larger than the pad.
2) For BGA, the solder mask should only expand by 1 mil.
3) The minimum solder mask bridge width should be 5 mils.
4) The solder mask window and paste layer should be opened on the RF power amplifier IC heatsink.
5) The metal shield frame should have openings for the solder mask and paste layer.
6) All vias should be defined as tented.
**6. Silkscreen Layer**
1) The silkscreen should not overlap with pads.
2) The silkscreen text should be properly aligned.
3) The height of the silkscreen characters should not be less than 20 mils, and the width should not be less than 5 mils. Text smaller than 6 mils should be avoided.
4) The board number and other important information should be placed in prominent locations.
**7. Vias**
1) Inspect the through-holes for the components one by one.
2) The via capacity for power traces should be considered.
3) Mounting holes should be defined as NPTH; otherwise, the hole ring must be at least 4 mils wide.
4) Vias should not overlap pads to prevent solder bridging during assembly.
5) If vias must overlap pads, ensure that the copper is turned off in those areas.
**8. Gerber Files**
1) Review the Gerber files layer by layer.
2) Verify the Gerber files by stacking the layers.
3) Ensure that the minimum green oil bridge width in the Gerber files is greater than 5 mils.
**9. PCB Output File Checks**
1) PCB schematic diagram.
2) DRC (Design Rule Check).
3) Gerber files.
4) Drilling files.
5) Assembly drawings.
6) Fabrication instructions.
The above steps highlight the essential items for PCB self-inspection. However, certain checks may not be necessary in all cases, such as solder mask inspection, the PICK PLACE of output files, or the board layout.
It is highly recommended to have a dedicated staff member for PCB review, focusing on the following:
1) Consistency with the mechanical layout.
2) Alignment with the standard component libraries.
3) Adherence to conventional design guidelines.
4) Inspection of silkscreen files and graphical elements.
5) Verification of drilling files and tooling files.
6) Completeness of the documentation submitted for review (layout files, mechanical drawings, technical requirements forms, etc.).
7) Comparison of the 1:1 layout drawing with the physical components.
8) Compliance with technical specifications.
If your have any questions about PCB ,please contact me info@wellcircuits.com
1. **Structural Design**
1) Verify the PCB floor plan and the printed structure diagram;
2) Check the location and diameter of the mounting holes;
3) Inspect the wiring constraint areas.
2. **Component Library**
1) Confirm the component sizes;
2) Ensure the BGA device’s silk screen frame strictly matches the size specified in the DATA SHEET;
3) Verify that the pin count of the component matches the definition in the DATA SHEET;
4) Check the MALE/FEMALE (male and female) designation;
5) Compare the transistor pins with the DATA SHEET;
6) Ensure the first pin of the IC or multi-pin connector is represented by a square pad;
7) The silkscreen logo for polar components should be clear;
8) Verify the position and diameter of the component positioning holes.
**3. Component Layout**
1) The components must not overlap.
2) The spacing between components should not be less than 8 mils.
3) Ensure that components comply with the restrictions defined in the no-go zones.
4) Structural part screws should not contact any traces.
5) Decoupling capacitors should be placed near the relevant components.
6) A 1mm or 1.5mm MARK point should be placed at the diagonal corners of the PCB.
**4. PCB Routing**
1) Verify that routing complies with the no-go area requirements.
2) Routing on adjacent layers should be perpendicular to each other.
3) Critical signal traces should be individually inspected.
4) Ensure that differential signal traces are routed in parallel and have equal lengths.
5) The power trace capacity should be checked.
6) Sampling resistors must be routed separately to the sampling points.
7) Remove any unused copper areas when applying copper fills.
**5. Solder Mask**
1) The solder mask window should be 2 mils larger than the pad.
2) For BGA, the solder mask should only expand by 1 mil.
3) The minimum solder mask bridge width should be 5 mils.
4) The solder mask window and paste layer should be opened on the RF power amplifier IC heatsink.
5) The metal shield frame should have openings for the solder mask and paste layer.
6) All vias should be defined as tented.
**6. Silkscreen Layer**
1) The silkscreen should not overlap with pads.
2) The silkscreen text should be properly aligned.
3) The height of the silkscreen characters should not be less than 20 mils, and the width should not be less than 5 mils. Text smaller than 6 mils should be avoided.
4) The board number and other important information should be placed in prominent locations.
**7. Vias**
1) Inspect the through-holes for the components one by one.
2) The via capacity for power traces should be considered.
3) Mounting holes should be defined as NPTH; otherwise, the hole ring must be at least 4 mils wide.
4) Vias should not overlap pads to prevent solder bridging during assembly.
5) If vias must overlap pads, ensure that the copper is turned off in those areas.
**8. Gerber Files**
1) Review the Gerber files layer by layer.
2) Verify the Gerber files by stacking the layers.
3) Ensure that the minimum green oil bridge width in the Gerber files is greater than 5 mils.
**9. PCB Output File Checks**
1) PCB schematic diagram.
2) DRC (Design Rule Check).
3) Gerber files.
4) Drilling files.
5) Assembly drawings.
6) Fabrication instructions.
The above steps highlight the essential items for PCB self-inspection. However, certain checks may not be necessary in all cases, such as solder mask inspection, the PICK PLACE of output files, or the board layout.
It is highly recommended to have a dedicated staff member for PCB review, focusing on the following:
1) Consistency with the mechanical layout.
2) Alignment with the standard component libraries.
3) Adherence to conventional design guidelines.
4) Inspection of silkscreen files and graphical elements.
5) Verification of drilling files and tooling files.
6) Completeness of the documentation submitted for review (layout files, mechanical drawings, technical requirements forms, etc.).
7) Comparison of the 1:1 layout drawing with the physical components.
8) Compliance with technical specifications.
If your have any questions about PCB ,please contact me info@wellcircuits.com
