Castellated Holes or Semi-Plated Board Edge Holes are one of the many special fabrication options that Bittele accommodates.

Castellated holes appear on the edge of PCBs typically as plated half holes. They can also be offset so that instead of a perfect semi-circle they appear as a small or larger portion of a broken circle.

At Bittele Electronics the hole size for castellated holes must be at least 0.5mm in diameter with space between hole edges to be at least 0.4mm.

The most common purpose of these castellated holes is the soldering of one PCB directly onto another PCB. You may be asking yourself why this is preferred over just soldering the components directly to the main PCB.

One reason is that by having a smaller subassembly PCB you can easily replicate certain parts of your circuit that you know are always going to remain unchanged. For example, you may have a circuit that includes an inverter, filter, or feedback loop that is not to be altered. These smaller sub-circuits can be mass produced, tested and or programmed on their own, and then later soldered on to a main PCB that contains other parts of the circuit.

Another reason is to use the castellated PCB as a breakout board for a particular part. There are multiple advantages to doing this such as:

1. Making the soldering and re-soldering of a difficult to assemble complex components such as high pin density or leadless components like LGAs, BGAs, or QFNs relatively simple.
2. Allows IC’s to be reusable without having to worry about damaging the IC directly.
3. It can be used to forcibly reorganize the pin layout of a component to suit the needs of the user.
4. Allows complicated components to be used with a breadboard when normally this would be a challenge at best.

When requesting a quote for a project that contains castellated holes please call out this special requirement in your email to us at sales@7pcb.comor in the fabrication notes of your project files.

Related Articles:

• Does Number of Drills Affect Fabrication Cost?
• Plated Half Holes PCB
• The Difference Between Counterbore and Countersink Holes
• Countersink Hole PCB
• PCB Part-to-Part, Part-to-Hole, and Part-to-Board Edge Spacing