EasyEDA Board Parameter Analysis
### Name differentiation
PCBIt Printed Circuit Boardis the abbreviation of , translated as printed circuit board, which is an integral part of electronic products. PCB is mainly composed of three parts: substrate, conductive circuit and components, and is the carrier of electronic components.
PCBAIt is an abbreviation Printed Circuit Board Assemblyof , translated as printed circuit board assembly, which refers to the assembly of components on a printed circuit board to form a complete electronic product. PCBA is the core part of the entire electronic product, which determines the performance, quality and reliability of the electronic product.
SMTIt is the abbreviation Surface Mount Technologyof , translated as surface mount technology, which is a technology that directly mounts electronic components on the surface of PCB. Compared with traditional plug-in technology, SMT can greatly improve the integration and reliability of PCB, reduce the volume and weight of circuit boards, and reduce production costs and failure rates. SMT technology is a very important part of modern electronics manufacturing.
Plate type
FPC soft board
FPC is the abbreviation of Flexible Printed Circuit (Flexible Printed Circuit Board), also known as FPCB (Flexible Printed Circuit Board)
A printed circuit board that can be bent and folded, usually made of polymer materials such as polyimide
The FPC board is often used to connect two electronic devices, or as a connection line inside some devices
Forming is an important step in making FPC boards. FPC boards are formed into the desired shape and size by methods such as thermocompression forming and stretch forming.
FR-4
FR-4 is a glass fiber reinforced epoxy material most commonly used in PCB platemaking
It has the characteristics of high strength, high modulus, low expansion coefficient and corrosion resistance
The disadvantage is that the density is high, the processing is difficult, and it is easy to absorb water, resulting in a decrease in performance
Aluminum plate
Aluminum substrate as the main body, with an insulating layer and a copper clad layer attached
Has good heat dissipation performance and excellent mechanical strength
Aluminum substrates are difficult to manufacture and costly, and are usually used in high-power, high-performance electronic products
Good thermal conductivity, so there is no need for a thick copper clad layer, so it can use a thinner copper clad layer
Thermoelectric Separation Copper Substrate
It is formed by adding a thermoelectric separation layer (thermoelectric separation layer) between the copper substrate and the insulating material.
The thermoelectric separation layer is a mixture of polymer materials and conductive particles (such as carbon black, graphite, metal powder, etc.), which can completely isolate the copper substrate from insulating materials, thereby achieving excellent insulation and electrical properties
Better insulation performance, better electrical performance, better thermal conductivity
The manufacturing process is more complicated and the cost is higher, so it is usually used in electronic products with high performance and high reliability requirements
Rogers Rogers high frequency board
With the advantages of stable dielectric constant, low loss, low noise, and low harmonics, it can reduce energy loss during high-frequency signal transmission and improve signal transmission quality
Mainly used in high-frequency fields such as wireless communication, satellite communication, radar, microwave communication, etc.
Low dielectric constant error, low loss, high thermal stability, high thermal stability
PTFE Teflon high frequency board
Polytetrafluoroethylene (PTFE) is a polymer material with excellent physical and chemical properties
Corrosion resistance: PTFE has extremely strong corrosion resistance and can resist the erosion of many corrosive media such as strong acids, strong alkalis, organic solvents and oxidants.
High temperature performance: PTFE has a melting point of 327°C, has excellent high temperature resistance, and can maintain stable physical and chemical properties at high temperatures.
Low coefficient of friction: PTFE has an extremely low coefficient of friction and can be frictionless under lubricated conditions.
Insulation performance: PTFE has excellent insulation performance and can maintain stable insulation performance under high temperature, high frequency and high voltage conditions.
PTFE is widely used in the manufacture of valves, pipes, seals, bearings, pumps and other corrosion-resistant and high-temperature, high-pressure mechanical equipment
Plate thickness
0.2mm: Usually used in high-density printed circuit boards (HDI PCB), such as small electronic products such as mobile phones and tablet computers.
0.4mm: Commonly used in small electronic products, such as handheld devices, digital cameras, etc.
0.8mm: Commonly used in small and medium-sized electronic products, such as routers, controllers, industrial control equipment, etc.
1.6mm: is the most common circuit board thickness, suitable for most common electronic products, such as TVs, computers, mobile phone chargers, etc.
2.0mm and above: commonly used in products that require high mechanical strength and stability, such as automotive electronics, industrial instruments, etc.
copper plating
Copper plating is the process of electrifying copper metal on the surface of a conductive substrate
Copper is a commonly used conductive material, which can provide excellent electrical conductivity and corrosion resistance, while also having good solderability and machinability
Commonly used copper thicknesses are 1oz and 2oz, corresponding to 35um and 70um copper thicknesses respectively
Solder mask coverage
Solder mask overlay is a protective layer applied to the surface of the PCB, usually green, red or blue. Solder mask coverage can cover the metal lines and pads of the PCB to avoid them being corroded or polluted by the external environment
Pad plating
HASL with lead refers to spraying tin alloy material containing lead on the pad, using the high permeability and good solderability of lead to form solder joints
Lead-free HASL refers to spraying lead-free tin alloy materials on the pads, but lead-free alloys have a high melting point, which is prone to poor soldering and requires special process control
Immersion gold is to clean the PCB first, then plate copper, and then soak it in gold salt to coat it with a metal layer
gold finger hypotenuse
The beveled edge of the gold finger means that the junction between the edge of the PCB board and the gold finger is treated with a bevel to ensure the fit between the gold finger and the socket and avoid problems such as poor contact during the use of the socket. Usually, the angle of the hypotenuse of the gold finger is 30 degrees or 45 degrees.
Via
There are two types of vias
- Through hole: A hole that passes from one side of the board to the other
- Blind hole: only through a part of the plate thickness, forming a blind hole on one side of the plate
The hole needs to be plated with copper or other processes on the inner wall of the hole to prevent the circuit from being polluted by the environment.
Pad
The PCB we see without soldering pins will have some small round holes for us to solder the pins ourselves. These holes are pads
A pad is an electronic component that is connected between an electronic component and a circuit board. It is a usually circular metal disc that holds the pins of electronic components.
On the circuit board, the role of the pad is to provide a reliable connection point for the pins of the electronic component to connect it with the electrical path on the circuit board.
A layer of solder paste will be coated on the pad, and the solder paste will be melted by heat during soldering, and the pins of the component and the pad will be welded together.
After the welding is completed, the contact between the pad and the pin is reliable, and the electronic components can be safely connected to the circuit board to complete the assembly of the circuit. Pads can also be used for hand soldering to connect electronic components and wires.