1. Blog>
  2. The advantages of SMD technology in comparison to THT components - An Talk

The advantages of SMD technology in comparison to THT components - An Talk

by: Apr 19,2021 2882 Views 0 Comments Posted in PCB Design Tutorial

PCB Design Tutorial PCB layout Circuit electronics easyeda

Summary:       In this short article we´re going to talk about SMD and THT component technology in comparision and its advantages/disadvantages.

Hi PCB-Designers out there,

Only through the use of so-called SMD components all necessary technical elements can be used on a platform with a short amout of surface. //The term SMD means surface-mount devices//

Forms of SMD-Components

SMD components (Surface Mount Devices) are the electronic function parts,  which are soldered to the circuit board by surface mount technology. There are many types of SMD components, and each type is packaged in different forms, which results in the huge SMD components library.

Generally, the three digits on the body of a chip resistor indicate its resistance value. Its first and second digits are significant digits, and the third digit indicates the multiple of 10, such as "103'' indicates "10KΩ", "472" is "4700Ω".

The most used are MLCC (Multi-layer Ceramic Capacitors), MLCC is divided into COG, X7R, Y5V according to the materials, of which COG (NPO) is the most stable.

Typical structures of transistors are NPN and PNP, including Triode, BJT, FET, MOSFET, and the like. The most used packages in SMD components are SOT-23 and SOT-223.

The standard sizes of SMD components are as follows,

History and comparison

In the course of the increasing miniaturization of electronic components, the components became smaller and smaller and other assembly methods had to be developed. This difference became very clear, especially when compared to conventional THT components (through-hole technology).

If these were permanently connected to the board with pre-drilled and plated-through holes, they had to be attached to the board by hand with solder. This problem was no longer the case by using SMD components.

Advantages of both

The advantage of this is the obvious gain in efficiency and cost savings,

Which is why I opted for these components, despite the challenges in my own assembly during the prototype phase of my AZ-Envy. The components (types) mentioned here are all in a very small one Format, inexpensive, as well as variably applicable.

Assembly of such components

PCBA means “PCB assembly” . When a printed circuit board is mounted with required electronic components, we call it a PCBA. A complete PCBA manufacturing process needs two assembly procedures – an SMT (surface mount technology) assembly and a THT (through-hole technology) assembly, which you can see above.

These days most of the designs use SMT components such as Inductors, resistors, compactors, ICs, etc.

They can be soldered on pads of the board using solder paste. A reflow soldering oven melts the solder paste and connects the SMT components with the board tightly.

The components which has the legs (THT components ) to insert in to the board’s drill holes and need to be assembled after the SMT assembly. Technicians use hands or machines to insert the component legs and then the assemblies go through a wave soldering oven to connect the THT components with the board. This process is called THT assembly.

When printed circuit boards are ready, you need to have them assembled with components. Usually, a PCB company doesn’t produce components but sources from their trusted suppliers. You can buy all components on your own and send them to the PCB company to assemble (PCBWay´s Turnkey), or provide special components and source basic components from the PCB company.

But in comparison:

Through-hole components are best used for high-reliability products that require stronger connections between layers. Whereas SMT components are secured only by solder on the surface of the board, through-hole component leads run through the board, allowing the components to withstand more environmental stress. This is why through-hole technology is commonly used in military and aerospace products that may experience extreme accelerations, collisions, or high temperatures. Through-hole technology is also useful in test and prototyping applications that sometimes require manual adjustments and replacements.

In this video you can see the use of both SMD and THT components on my PCB by PCBWay, thanks!

So overall its very important to look at your project needs and its cost during production!

Hope you´ve learned a bit!


Join us
Wanna be a dedicated PCBWay writer? We definately look forward to having you with us.
  • Comments(0)
You can only upload 1 files in total. Each file cannot exceed 2MB. Supports JPG, JPEG, GIF, PNG, BMP
0 / 10000
    Back to top