SMT, surface mount technology, places components with flat terminations or short leads onto pads printed with solder paste, then solders them all at once in a reflow oven. It allows tiny parts, assembly on both sides and very fast automated placement, and dominates electronics production. Parts made for it are called SMDs, ranging from passive chips in 0402 and 0201 sizes up to large BGAs and QFNs.
Top side is all SMT, the bottom only has the connectors, so it's one reflow pass plus selective solder.
Also heard as
- surface mount
- surface mount technology
Related terms
Reflow
Soldering surface mount parts by melting printed solder paste in an oven that follows a set temperature profile.
Solder paste
Mix of fine solder powder and flux printed onto pads to hold parts in place and form the joints in reflow.
Pick-and-place
Automated machine that picks surface mount parts from reels and trays and sets them on a pasted board.
Through-hole
Mounting method where component leads pass through plated holes and are soldered on the far side.