When preparing to design a printed circuit board, it is necessary to determine the surface mount and through-hole packaging of certain components. Compared with traditional through-hole components, SMT surface mount technology has many advantages, but there are also some disadvantages. The following Sanjing Let’s understand:

First of all, let's first understand the advantages of SMT surface mount:

①Automated assembly: Compared with manually assembled PTH parts, most SMT parts can be easily installed on the circuit board using automated pick-and-place equipment. High-capacity parts (such as passive parts) are loaded from the reel into the pick-and-place machine, while others Parts are loaded from tube feeders or pallets.

②The versatility of parts on PTH: SMT parts are usually smaller in size and volume than PTH parts, because there are no long leads that need to be inserted and soldered into the holes, so more components can be installed on a smaller board and then used PTH components.

③Electrical performance: Compared with PTH components, due to the size, there are more SMT components mounted on the board, so the signal path on the board becomes shorter, which can provide better signal integrity for the PCB and reduce the heat generated. .

Although most printed circuit boards now use SMT parts, sometimes PTH parts are also considered for problems. Let's take a look at the shortcomings of SMT surface mount:

①Not easy to use: Although reworkers are good at using tweezers and magnifying glasses to rework small SMT parts, it is troublesome to find, desolder and re-soldering after replacement. At the same time, because the parts are relatively dense, the handheld soldering iron may also damage nearby parts.

②Electrical performance: Although SMT components can provide better signal performance due to their small size, high-power applications still require larger PTH components.

③Mechanical strength: SMT components usually use disposable connectors, but stronger connectors should be used in frequent connection or disconnection applications. At this time, PTH components are the best choice because of its solder through-hole leads. Surface-mounted soldered parts have higher mechanical strength.

The above is about the advantages and disadvantages of SMT in PCB assembly, I hope it can be helpful to everyone!