How many types of pads are there in PCBA circuit boards?

The types of pads in PCBA can be classified according to their use and design. There are mainly the following types:

1. Surface Mount Pad (SMD):

This pad is used to mount surface mount components such as chips, capacitors, inductors, diodes, etc. SMD pads are usually small, flat, and located on the surface of the PCB.

2. Plated Through-Hole (PTH):

The plated through-hole pad connects the two sides of the PCB through a hole and is usually used for the connection of plug-in components such as sockets, connectors, and stud terminals.

3. Non-Plated Through-Hole:

These pads are similar to through-hole pads, but they are not coated with conductive materials and are therefore non-conductive. They are usually used for mechanical support or PCB alignment, not for electrical connection.

4. Thermal Pad:

The thermal pad is usually used for the connection of heat sinks or heat dissipation components to effectively disperse the heat generated by electronic components.

5. CASTELLATION:

This pad is shaped like the teeth of a castle and is usually used for the external pins of a BGA (Ball Grid Array) package for connection and testing on a PCB.

6. Filled Vias:

Filled Vias are pads filled with conductive materials through processes such as through-hole plating to provide better electrical performance and reliability.

7. Controlled Impedance Pads:

This pad has a specific geometry and size and is used to control the signal impedance on the PCB to ensure stable transmission of high-frequency signals.

Some common pad types are listed above, but other customized pad types can also be created based on specific PCB design and application requirements. Choosing the appropriate pad type depends on the function of the board, component type, performance requirements, and manufacturing process.