Definition

Surface Mount Technology (SMT) is the assembly process for mounting SMD components using automated placement and reflow soldering. For PCB designers, SMT-compatible design means: pads sized per IPC-7351, consistent pad orientation for wave or selective soldering if mixed with through-hole, thermal relief on pads connected to planes (prevents tombstoning from uneven heating), and adequate spacing for pick-and-place nozzles (typically 0.5mm between component bodies). Fiducial marks on the PCB help machine vision align placement. Design for double-sided SMT requires consideration of which side reflows first.