7351C draft was worked on for 3 years and eventually discarded because Dieter Bergman the architect passed away PCB Libraries Do We Have a New Release of IPC-7351C? - PCB Libraries
The development of IPC-7351C was famously stalled and eventually scrapped in favor of starting fresh with
Key changes include moving from a specifying rounded rectangle pad shapes with corner radii, ipc-7351c pdf
: Replaced the older "3-tier" pad stack concept with a system that scales annular rings proportionally based on hole diameters. Rounded Rectangle Pads
Footprints naming convention: IPC-7351 vs. Expert - PCB Libraries 7351C draft was worked on for 3 years
IPC-7351C was designed to modernize the way footprints (land patterns) are calculated, moving away from fixed library definitions toward dynamic, math-based generation. Although the committee eventually pivoted, several "What's New in IPC-7351C" documents from PCB Libraries and industry experts detail the intended core changes. PCB Libraries Key Features and Changes
: Introduced recommendations for local fiducials on fine-pitch components (pitch smaller than 0.635mm for QFPs or 0.8mm for BGAs). Revised Naming Conventions : Expanded the footprint naming convention Expert - PCB Libraries IPC-7351C was designed to
: Recommended using rounded rectangles instead of standard rectangles or oblong shapes to improve solder paste release and consistency. Contour Courtyards
to include more data points like thermal tab sizes and terminal lead dimensions to prevent duplicate names. PCB Libraries Current Status: IPC-7351B vs. IPC-7352 IPC-7351B (Current Standard) IPC-7352 (Newest Guideline) Release Date February 2023 Technology 100% Surface Mount (SMD) SMD + Through-hole (THT) Document Type Official Standard Pad System 3-Tier Fixed (Most, Nominal, Least) Proportional Pad Stacks
The "C" revision introduced several major shifts in PCB design philosophy: Proportional Pad Stacks