What's Wrong with Your Footprint?!

Footprint Expert

Source 1

Source 2

AUTO-GENERATED library parts use predefined or user-modified rules – share across your organization;
RULES-based, auto-generated part library

MANUALLY CREATED by many different people, using countless rules – results in a board with inconsistently built parts, far more prone to introduction of costly errors; massive variations in parts inconducive to standardized rule-based library

Built to exact datasheet specification, either Metric or Mils

Units vary based on source, and Metric often converted from Mils with rounded-off measurements; converting pin pitch often results in leads not fully centered on pads

User-defined consistency of line widths for all parts

Many different line widths used across different footprints due to lack of standard rules

Accurate contour courtyards are auto generated

Sloppy or non-existing contour courtyards

Relevant data: Footprint Name, Physical and Logical Descriptions, datasheet link, and more

Nothing, or inconsistent random data

Auto-generated keep outs on all non-plated holes for copper poly shapes, traces and vias

Missing keep-out will cause DRC errors at the manufacturer if copper, traces, and vias are placed within 0.25 mm of the non-plated hole

Pin 1 polarity markers for silkscreen and assembly

Pin 1 markings missing or vary in shape and in size

Footprint Origin at center of gravity

Footprint Origins randomly placed

Uniform, silkscreen outlines are whole objects mapped to the maximum package dimensions

Silkscreen is fragmented and mapped to the nominal package dimensions

Clear, consistent, intelligently placed markings to minimizes use of board space

Inconsistent and extra markings and excessive courtyards requires more placement space

Consistent silkscreen trimming around all pads

Inconsistent and random silkscreen trimming around pads

Solder Mask swell auto-applied and configurable

Inconsistent solder mask swell from one footprint to another

Through-hole pad stack hole sizes automatically defined by maximum terminal lead diameter, and pad size auto-calculated by 1.5 x hole diameter

Lack of published, consistent rules to define through-hole pad stacks make it impossible for proper quality control of resulting footprint, results in capriciously calculated footprints

Non-plated holes have smaller pad sizes to prevent copper slivers after drilling process

Non-plated holes have a pad size equal to the hole size create risk of copper slivers after the drilling process; the plane antipad is randomly defined with no obvious rules