While the primary reason for moving to surface mount technology was related to cost, speed, and reliability, there are other benefits. This technology has had a huge impact on the way that people today design and develop new circuits and equipment. The good thing about this is that the change has largely created advantages rather than disadvantages. Some things to be aware of for developers using surface mount technology are listed below.
- Circuits Are Smaller and Denser Than Ever – The electronics industry has always had the drive to offer more function in smaller packages, but that was never an easy task before surface mount technology became widespread. SMT is designed to make this simple since everything is in a miniature format. Components can be extremely small and mounted closer together on the circuit board than would ever be possible with typical components with leads. This, combined with the better functionality available through integrated circuits, makes life easier for a development engineer.
- Lower Power Rating Requirements – One of the most important things to look for when designing and producing electronics is the power rating of the components. With surface mount technology, devices can have lower power ratings than ever before. As an example, a standard resistor with a lead can dissipate 0.25 watts or even more. However, surface mount resistors are smaller so the dissipation is also lower. People should be aware of this during a build but always make sure to check the manufacturer’s data for the exact numbers.
- Less Inductance and Spurious Capacitance – Since surface mount technology components are smaller, that also means that spurious inductance and capacitance are also going to be smaller. An SMT resistor, to keep with the previous example, will be closer to an ideal resistor than a resistor with leads. In the same way, a surface mount technology capacitor is going to create less parasitic inductance. When taking this all together, standard SMT components will have higher frequencies and faster speeds than leaded components are capable of.
How to use surface mount technology during PCB assembly?
Nowadays, SMT is used in almost all facets of PCB manufacturing and assembly. More electronics can be placed in a smaller space using the technology. All of the components are smaller and many of them offer better performance than traditional components. They also can be easily used with automated machines to eliminate the need for worker intervention during the assembly process.
With wired components, it was always a challenge to rely on automatic placement. All wires had to be pre-made to fit the correct hole spacing and, in some cases, there were still issues with placement. PCB assembly typically has all components placed automatically. Manual assistance might be occasionally needed but it is rare. High-quality circuit boards reduce the need for this to the point of even changing a design so components fit perfectly.
One issue that used to be common with surface board technology components was their lack of resistance to heat. Since the components are soldered in, this raises the temperature of the part and could cause issues in some situations. However, new components have been developed that have no problem tolerating the temperatures associated with the soldering process.