The standard expands the Footprint Naming Convention to include more complex component types like BGAs with dual pitch and staggered pins.
Large pads for high-reliability applications (military/medical) where rework and hand-soldering are common.
: The work intended for 7351C was largely integrated into the newer IPC-7352 , Guideline for Generic Requirements for Surface Mount Design and Land Pattern Standard . Key Features Intended for IPC-7351C ipc-7351c pdf
Footprints naming convention: IPC-7351 vs. Expert - PCB Libraries
Industry sources indicate that even if IPC were to complete their revision, “it’s not going to be much different than 7351B,” and much of the proposed innovative content has been discarded. The standard expands the Footprint Naming Convention to
Many legacy PCB libraries are based on Revision B. If you are still using an older "IPC-7351B PDF," you are missing critical updates. Here are the primary differences in Revision C:
Some key topics covered in the IPC-7351C PDF include: If you are still using an older "IPC-7351B
The IPC-7352 naming convention was also expanded to include additional critical data like Thermal Pad sizes and other missing package information, and it further refined the mathematical model by removing fabrication and assembly tolerances for pad stack calculations.
The problem? Every company invented its own rules. One engineer’s pattern for a small transistor might be too small, causing the part to tombstone (stand up vertically during soldering). Another’s might be too large, creating weak solder joints that crack over time. There were no standards. A design that worked for a prototype might fail catastrophically on a high-speed assembly line.