The Impact of Lead-Free on DESIGN AND FABRICATION

摘要

The advent of lead-free manufacturing is impacting PCB design and fabrication, but its effect on design is minimal. Fortunately for designers, in general, the design rules for lead-free soldering are similar to those for tin-lead soldering. Many steps in the design process - bringing up the netlist, making physical aspects of components or footprints, assuring component connections are correct, and making board thickness calculations for impedance control or dielectric constant calculations - do not typically change with lead-free. When designing a board that's bound for lead-free assembly, the main concern is the physical footprint on the board. If component packaging is manufactured to withstand the higher temperature for lead-free assembly, then there should be no change in the footprint and, consequently, no change in the layout.