PCBmanufacturerChina learned the reason electronic devices can perform different functions is that the internal PCBA board provides it with various capabilities.We usually refer to the printed circuit board in the equipment as PCB, which is actually not the correct name.The printed circuit board itself cannot work, it acts as a carrier for the electronic equipment, and the PCBA board is the main body that makes the electronic equipment work.

 

The smartphone you use has a long, uncluttered line.The main function of these lines is to integrate the hardware devices of the mobile phone into a single PCBA, including Wi-Fi, antenna, GPS, fingerprint sensor, etc.In the following content, FS Technology will take a mobile phone as an example to introduce how the circuit board works.

 

 

How does the circuit board work?

 

The reason electronic devices can perform different functions is that the internal PCBA board provides it with various capabilities.We usually refer to the printed circuit board in the equipment as PCB, which is actually not the correct name.The printed circuit board itself cannot work, it acts as a carrier for the electronic equipment, and the PCBA board is the main body that makes the electronic equipment work.

 

The smartphone you use has a long, uncluttered line.The main function of these lines is to integrate the hardware devices of the mobile phone into a single PCBA, including Wi-Fi, antenna, GPS, fingerprint sensor, etc.In the following content, FS Technology will take a mobile phone as an example to introduce how the circuit board works.

 

Basic concepts of circuit boards

 

PCB: Also known as circuit board, printed circuit board, PWB, bare board.You may have seen a board like this, it may be green or some other color.What appears to be a simple circuit board is actually a multi-layered labyrinth of hundreds of copper wires.The PCB provides support and effective blocking for all components mounted on its surface, and the lines in the middle of the board provide a platform for communication and collaboration between components.

 

PCBA: The abbreviation of PCB assembly, although it is only one letter more than PCB, there is an essential difference between the two.Usually, we call the conductive pattern formed by the combination of the circuit and the printed component on the insulating material according to the predetermined design as the PCB, and the board on which electronic components have been installed is called PCBA.The PCBA board is an electronic component that plays a decisive role in electronic products.

 

 

SMT assembly: an assembly technology that mounts SMD components on a bare PCB. The full name of SMT is surface mount technology.

 

THT assembly: A traditional technology for installing plug-in components on bare boards. The full name of THT is through-hole technology.

 

How Printed Circuit Boards Work?

 

PCBs are made by isolating the surface copper foil conductive layer through the board base insulation material, which allows current to flow through various components along a pre-designed route, ultimately achieving functions such as power making, amplification, attenuation, modulation, demodulation, and coding.This is a description from a PCBA government website.It may not be easy for non-industry practitioners to understand.FS Technology will disassemble the working principle of the entire mobile phone PCBA to show you.

 

The composition of the PCB board

 

This smartphone PCB is actually made up of ten conductive layers, the top and bottom layers of which are used to mount the PCBA components and act as multiple antennas. In order for it to function properly, power and ground planes are included on every circuit board.

 

In addition, the ground plane also has the functions of electromagnetic shielding and heat dissipation. The remaining four intermediate layers are used to carry all communication lines or signal lines. Each conductive layer contains copper and insulating fiberglass and epoxy. The smartphone PCBA shown here has only 10 conductive layers, but in other applications they can have 2 to 50 more layers. FS Technology can produce multilayer PCBA with up to 56 layers.

 

 

In addition, on the top and bottom of the PCBA is a layer of colored solder mask, which acts as an electrical insulation and thus makes the pads of the components available. Above it is silkscreen, including ink for marking and letters indicating the location of the components.

 

For the circuit board to function properly, the signal must pass through each conductive copper layer and the insulating material between them. This smartphone has ten separate layers of conductive copper and insulating material between each layer. How does the signal propagate from one layer to another?

 

The PCB layers perform this function by drilling or metal plating the signals through vias or vertical interconnects. These vias connect the wires of each layer to each other, thereby connecting multiple components and realizing the work of multi-layer boards. There are three types of vias that can be achieved with the PCB manufacturing technology of Chinese manufacturers.

 

Through Hole: A hole from the top layer to the bottom layer

Blind Vias: Blind vias connect the top or bottom layer to the middle layer

Buried Vias: while buried vias connect internal layers

 

 

Since this process requires traversing many layers, when traversing unconnected conductive layers, the copper around the vias on that layer is removed. If we take an X-ray to look at the pads on the top of the PCB for mounting, you can see three sets of wires running in different directions, while holes go through each layer.

 

These complex wires exist on the PCB in the center of the phone, and they are so incredible. Each model of smartphone is different in shape and specification, so engineers need to use PCB design tools to design different types of PCBA. For example, some mobile phones have separate top and bottom PCB boards, the larger one is called the main board and the smaller one is called the daughter board.

 

 

Another important detail is that the PCB is lighter, weighing only a tablespoon of water, and will fit nicely in your phone. Engineers are constantly innovating to make microchips, resistors, capacitors, inductors, and connectors as small as possible, with some components smaller than a flea.

 

 

 

 

FPCsupplier learned in the past, PCBA board designs used components that took up too much board space and board space. Since the mounting mechanism for these components is that the pins pass through the connection holes, these older designs are called through-hole components. But here, these components are SMD components mounted by SMT assembly technology.