Why IPC-D-356A Netlists Are Critical to PCB Manufacturing
An IPC-D-356A netlist provides an independent electrical reference that helps PCB manufacturers verify design data from initial file review through final electrical test. Providing the IPC-D-356A file generated directly from your CAD system gives the manufacturer an additional level of assurance that the Gerber files accurately represent your intended electrical design.
As an industry best practice, PCB manufacturers recommend customers provide an IPC-D-356A net list file with their gerber data files.
What Is an IPC-D-356A Netlist?
IPC-D-356A is an intelligent electrical test data format that identifies the electrical connectivity of a printed circuit board, including nets, pads and plated through-hole locations. When generated directly from the PCB CAD system, it provides an independent reference that can be compared against the Gerber fabrication data supplied to the PCB manufacturer.
Why Provide an IPC-D-356A Netlist?
1. Verify the Gerber Files
The IPC-D-356A file is typically generated directly from the CAD system at the same time as the Gerber output. Because it originates from the source design, it provides an independent reference that can be compared with the Gerber fabrication files.
The IPC-D-356A file is typically generated directly from the CAD system at the same time as the Gerber output. Because it originates from the source design, it provides an independent reference that can be compared with the Gerber fabrication files.
2. Identify Data Discrepancies Before Manufacturing
When Westak receives both the Gerber files and IPC-D-356A netlist, the two can be compared during incoming data review. Differences can be identified and resolved with the customer before PCB manufacturing begins.
When Westak receives both the Gerber files and IPC-D-356A netlist, the two can be compared during incoming data review. Differences can be identified and resolved with the customer before PCB manufacturing begins.
3. Protect Electrical Design Intent During CAM
During CAM tooling, the netlist provides a reference that helps identify unintended changes that could affect the electrical functionality of the PCB.
During CAM tooling, the netlist provides a reference that helps identify unintended changes that could affect the electrical functionality of the PCB.
4. Support Final Electrical Test
The IPC-D-356A netlist can also be used during electrical test to confirm that the manufactured PCB electrically correlates with the customer-supplied fabrication data.
The IPC-D-356A netlist can also be used during electrical test to confirm that the manufactured PCB electrically correlates with the customer-supplied fabrication data.
Why a CAD-Generated Netlist Is Better Than a Gerber-Extracted Netlist
A netlist extracted from the Gerber files does not provide the same independent verification as a netlist generated directly from the original CAD design.
If an electrical feature is missing, altered or incorrectly translated in the Gerber files, a netlist subsequently extracted from those same Gerbers may contain the same error. The resulting netlist could then be used during CAM and electrical test without identifying the original discrepancy.
Best practice: Generate the IPC-D-356A netlist directly from the PCB CAD system and submit it with the original Gerber fabrication package.
If an electrical feature is missing, altered or incorrectly translated in the Gerber files, a netlist subsequently extracted from those same Gerbers may contain the same error. The resulting netlist could then be used during CAM and electrical test without identifying the original discrepancy.
Best practice: Generate the IPC-D-356A netlist directly from the PCB CAD system and submit it with the original Gerber fabrication package.
IPC-D-356A Verification Throughout PCB Manufacturing
One File. Multiple Levels of Verification.
CAD Data → Incoming Data Verification → CAM Tooling → Final Electrical Test
The IPC-D-356A netlist provides an independent electrical reference throughout the PCB manufacturing process.
The IPC-D-356A netlist provides an independent electrical reference throughout the PCB manufacturing process.
IPC-D-356A Frequently Asked Questions
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Do PCB manufacturers require an IPC-D-356A netlist?
Not always, but providing one is strongly recommended because it allows the manufacturer to independently compare the intended electrical connectivity against the fabrication data. Should the IPC-D-356A netlist be generated from the Gerber files?
Ideally, no. The greatest value comes from generating the IPC-D-356A file directly from the original PCB CAD system. What happens if the IPC-D-356A netlist does not match the Gerber files?
The discrepancy should be reviewed before manufacturing to determine whether the Gerber data, netlist or design output requires correction. Is an IPC-D-356A netlist used for PCB electrical testing?
Yes. It can provide the electrical connectivity reference used to verify that the finished PCB correlates with the fabrication data supplied by the customer. |
For additional recommendations on preparing files for PCB manufacturing, review our PCB Tooling Package requirements and Design Guidelines.
Ready to submit your PCB data?
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