Land Patterns vs. Footprints: What’s the Difference?
The terms “land pattern” and “footprint” are often used interchangeably in the PCB Assembly industry, and while these terms are similar, there is some nuance that draws a distinction between them. Some might say that this distinction is overly pedantic, but in truth there are instances where it is functionally useful to understand the difference. In fact, a specific component could have multiple different land patterns, but it will always have a single footprint.
A component’s footprint officially refers to the actual physical size of a given component. If you were to painstakingly measure the body and the leads of a given component and draw out a picture using those dimensions, you would then have the part’s footprint. To put it in a more relatable way, the footprint of a component is much like the footprint of a person: it is the imprint that component would create if you were to press it down in soft sand.
The land pattern refers to the size of the pads and outline for a given part that should be designed onto a PCB. Both Manual and Automated Soldering processes require that the pads designed for a parts should be larger than the leads to which they will be soldered, so the land pattern should always be slightly larger than the footprint for any component. You can normally find land pattern recommendations in manufacturer datasheets.
One of the most important aspects of Bittele’s comprehensive DFM Check service is our footprint vs. land pattern comparison. Before PCB Fabrication begins, our expert Quality Management engineering team will compare the land patterns for each part in your design with documented footprint dimensions to ensure a High Quality PCB Assembly. This service pre-empts manty Common PCB Defects than can occur due to land patterns being either too large or too small for their associated footprints.
Please do not hesitate to Contact Us if you still find yourself with any remaining questions about component footprints and component land patterns. We can be reached via email at firstname.lastname@example.org, or toll-free at 1-888-812-1949.