What is the Difference between SMD and Through-Hole Components?

In this tutorial, we are going to learn about the Difference between SMD and Through-Hole Components.

What is SMD Component?

  • SMD – Surface Mounted Device (SMD), which don’t require any PTH as the component will be soldered on the component side itself as shown in below image of SMD components mounted on PCB.
  •  SMD is an electronic device for that the components are mounted directly onto the surface of the Printed circuit board (PCB).
  • SMD components are mounted by Surface Mounted Technology (SMT), SMT is a method for producing electronic circuit in which the components are mounted or placed directly onto the surface of printed circuit boards (PCBs).

SMD Components of Types:

  • SOT – Small Outline Transistors, Like SOT-23.
  • SOIC – Small Outline Integrated Circuit, Like SOP-8.
  • PLCC – Plastic Leaded Chip Carriers, Like PLCC – 48.
  • SOJ – Small Outline J Packages, like SOJ – 32.
  • QFP – Quad flat package, like QFP-64.
  • BGA – Ball Grid Array, like BGA – 80.

What is Through Hole Component?

  • Through Hole Component – Through hole components will require a PTH (Plated Through Hole) in PCB as the component lead will be soldered on the solder side (bottom side) of PCB. As below image for

Mounted of Through Hole Component on PCB.

  • It can be mounted on a PCB  to a hole that is drilled from the top and through to the bottom of a PCB,
  •  It can be PTH (Plated Through Hole)  and  NPTH (non-plated through hole).
  • Today, PCB’s are designed by all SMD components or maximum number of SMD components.

Through holes Components of Types:

  • Axial Leads components – these types of components which lead can be placed on both end sides of the component.
  • Radial Leads components – These components which lead can be mounted on one end side.

Why SMD components Use More than Through Hole Components?

  • SMD components are smaller size.
  • It much higher component density (components per unit area) and many more connection per component.
  • SMD component lower initial cost and time required during manufacturing as fewer holes need to drill in the PCB.
  • SMD component is simpler and faster automatic by SMT.
  • SMD components can be placed on both side of the PCB.
  • SMD components have lower resistance and inductance at the connection, consequently, fewer unwanted RF signals effects and better and more predictable high frequency performance.
  •  SMD components are better mechanical stability under shake and vibration conditions.
  • SMD components better EMC compatibility due to smaller radiation loop area.

Leave a Comment