A2Ts output their PCB design
database into Gerber Files, as commonly done. This particular design
specifically called for square pads on the plane layers. However, the output showed
round clearances on the plane layers. The CAD system's DRC approved this
discrepancy with no problem.
The Gerbers were sent to fabrication...
- PCB CAD design rule checking validates design with no clearance violations including plane layer connectivity
- Gerber files created with square pads on plane layers with round clearance pads
The fabricated bare boards FAILED due to large number of
shorts on the plane layers.
With Translation Comes Risk
Verifying the CAD netlist matches the final netlist extracted from the Gerber
will ensure original design intent is maintained. Netlist Comparison is key in this
process. Many common errors uncovered through Netlist Compare include:
- Accidental inclusion/exclusion of traces, vias, etc on Signal layers
- Text or reference designators placed on signal layer instead of a silkscreen
- Placement of drafting items on ALL layers instead of specific layers
The Result
After the bad boards were produced, A2Ts requested CAM350 software be brought in to trouble shoot the problem. Netlist
Compare immediately detected the plane layer mismatch. Precautions were taken,
discrepancies resolved,
and successful boards were produced.
In Conclusion
A2Ts now uses CAM350 as the final validation before
committing any designs to Fabrication.
Netlist Compare
Netlist Compare literally compares two netlists. It accurately compare your original CAD netlist with
the extracted one in Gerber or with your fab house's artwork.
