: 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
Key changes include moving from a specifying rounded rectangle pad shapes with corner radii,
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 ipc-7351c pdf
The "C" revision introduced several major shifts in PCB design philosophy: Proportional Pad Stacks
, which officially includes through-hole guidelines that were missing from the 7351 series. PCB Libraries Where to Find Resources IPC-7351C Land Pattern Overview | PDF - Scribd PCB Libraries Key Features and Changes The "C"
The development of IPC-7351C was famously stalled and eventually scrapped in favor of starting fresh with
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 ipc-7351c pdf
: Moved from strictly rectangular component "courtyards" (the keep-out area) to contour-based courtyards that follow the actual shape of the component to save board space. Local Fiducials
Footprints naming convention: IPC-7351 vs. Expert - PCB Libraries