In Circuit Test Nodal Access Layout Rules for Assembly Verification
Ensuring complete bottom-side nodal access with standard pad pitch and strain-mitigated fixturing locks in fault coverage and prevents field defect escapes.
IPC-D-356
Data Format
Standardized netlist file format used to communicate electrical test information between design and manufacturing. The IPC-D-356 specification defines the coordinates, net names, layer assignments and pad sizes for every testable point on a printed circuit board. Automated test equipment uses this data to verify that the physical board matches the original schematic.
Connectivity Verification
Automatic test program generation relies on the specific pin and node data contained in the file. By comparing the extracted netlist from the finished copper to the IPC-D-356 file, the system identifies opens and shorts. Every record in the file includes a net name that links various physical locations together into a single electrical node.
Discrepancies between the Gerber data and this netlist often signal a translation error during the CAM process.
Test Execution
Modern versions of the format include more complex information about mid-points and component pins. An IPC-D-356 record identifies the side of the board and whether the point is a through hole or surface mount pad. Higher density boards require the 356A version which supports more elaborate pad geometries and multi-layer structures.
Using this file ensures that the electrical test covers every intended connection while ignoring non-conductive mechanical features. Testing efficiency depends on data integrity.