What are the uses of castellation PCBs?

castellation PCBs

High density, multi-function, and miniaturization have become more prevalent as electronic products have progressed in their development. The geoSmetric index of the boards is rising day by day, while the size of the printed circuit boards (PCBs) is decreasing. As a result, an upgrade to the soldering process is required. If you solder a circular hole to a motherboard using soldering flux, you will get cold solder, not hot solder. Because of this, there will be a less than optimal electrical connection between the motherboard and the daughterboard. This is mostly owing to the enormous size of the hole. As a result, the electrical product will be unable to function correctly. As a result, the need for plated half holes continues to grow with each passing day.

What are Castellated Holes on a printed circuit board?

When it comes to Castellation PCBs boards, Castellated holes are indentations made on the borders of the board to accommodate the plating of the half-holes. They are referred to as castellations in certain circles. This kind of hole is referred to as a semi-plated hole in this context. It is possible to place one PCB board on top of another using the holes provided. It makes the assembling procedure considerably more convenient for everyone involved.

The shape of these holes may vary depending on the application, and they may be a part of a broken circle in some instances. These castellations aid in the alignment of the two boards by distributing the weight evenly between them. As a result, it aids in the proper soldering of circuit boards. When it comes to board-to-board soldering, the castellated holes make it easier to connect the boards.

Castellations may be found in a variety of PCB modules, including Wi-Fi and Bluetooth modules, among others. Despite the fact that they are separate components, these modules may be soldered together while still in the soldering process. These castellated holes are used to link two printed circuit boards (Castellation PCBs) together directly.

However, the system as a whole is significantly thinner than a connection made using multi-pin connections, which would otherwise be the case. When it comes to PCB assembly procedures, Through-Hole Technology and Surface Mount Technology are two of the most frequently utilized technologies available. It is also common to use board-to-board soldering when two printed circuit board (PCB) boards must be joined together. The use of castellated holes creates the connection between the board and the module.

What is the purpose of using Castellated holes?

The castellated holes are located on the borders of a printed circuit board (PCB). They are capable of replicating numerous components of a printed circuit board circuit. Consider the following scenario: we have a circuit that contains a filter or an inverter. We have the capability of mass-producing these small sub-circuits. Then we may connect them to the main printed circuit board (PCB), which contains the other components of the circuit. Thus, the castellated holes serve to duplicate that specific section of the main printed circuit board. Castellated printed circuit boards (PCBs) may be used in a variety of ways, including the following: as breakout boards for a specific region of a larger PCB.

  • We may modify the pin arrangement of the component by using these castellated holes as needed.
  • Castellation PCBs may be stacked on top of one another with relative ease.
  • Castellated holes are used to connect two PCB boards and check the soldering junction’s integrity.
  • We may build integrated modules on a single printed circuit board (PCB) using this technique. It is possible that these modules will be used in another assembling procedure.
  • This technique is commonly used by breakout boards and small modules like Wi-Fi modules.
  • Castellated holes may also be used to create wireless PCB-to-PCB connections.

Design of Castellated Holes/Visas

The castellated holes/vias are produced using a standard technique, which involves drilling holes and plating copper. On the edges of the board, these holes appear as semi-circles because they have been cut through to produce a partial hole or half hole, which allows for an opening to be created on the board edges. Half Holes Holes with smaller cut-in Half Holes Holes with smaller lead-in holes for post-processing Half Holes Holes with smaller cut-in Half Holes Holes with smaller lead-in holes for post-processing: They are intended for connector applications.

There are several design considerations for castellated holes that must be taken into consideration:

  • Size: Use the biggest available size.
  • Surface Finish: The surface finish of the board is determined by the intended application of the board. It is suggested to use an ENIG finish.
  • Design of the Pad: It is suggested that you use the biggest feasible pad on both the top and bottom of the pad.
  • Number of Holes: The number of holes required is determined by the design. Always aim for the fewest number of holes possible; otherwise, the alignment and assembly procedure will be more complex.

Various applications for Castellated holes on printed circuit boards are found in a variety of sectors, including telecommunications, computer applications, industrial control, electricity, automobiles, and high-end consumer electronics, among many others.


Castellated holes are an absolute necessity. They are widely used in a variety of applications, including computer applications, vehicles, industrial control, and telecommunications.

The most frequent use for these castellated holes is the direct soldering of one printed circuit board to another printed circuit board. The reason why this is preferable over just connecting the components directly to the main PCB may be beyond your comprehension.

A primary reason for this is that having a smaller subassembly PCB allows you to more quickly duplicate specific sections of your circuit that you know will always be the same. Suppose you have an inverter, filter, or feedback loop in your circuit that you do not want to change at any point. They may be mass-manufactured, tested, and programmed on their own before being connected onto a main printed circuit board (PCB) that includes the rest of the circuit components.

Read More: What One Should Know About Castellated Wrench?


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