Printed circuit board(PCB), also known as printed circuit board. It is not only the carrier of electronic components in electronic products, but also the provider of circuit connection of electronic components. The traditional circuit board uses the method of printing etchant to make the circuit and drawing, so it is called printed circuit board or printed circuit board.
PCB history:
In 1925, Charles Ducas of the United States printed circuit patterns on insulating substrates, and then established wires by electroplating. This is a sign of opening modern PCB technology.
In 1953, epoxy resin began to be used as substrate.
In 1953, Motorola developed a double-sided board with electroplated through-hole method, which was later applied to multilayer circuit boards.
In 1960, V. dahlgreen pasted the metal foil film printed with the circuit into the plastic to make a flexible printed circuit board.
In 1961, hazeltime Corporation of the United States made multilayer boards by referring to the electroplating through-hole method.
In 1995, Toshiba developed b21t additional layer printed circuit board.
At the end of the 20th century, new technologies such as rigid flex, buried resistance, buried capacity and metal substrate are emerging. PCB is not only the carrier to complete the interconnection function, but also a very important component of all sub products, which plays an important role in today's electronic products.
Development trend and Countermeasures of PCB design
Driven by Moore's law, the electronic industry has stronger and stronger product functions, higher and higher integration, faster and faster signal rate, and shorter product R & D cycle. Due to the continuous miniaturization, precision and high speed of electronic products, PCB design should not only complete the circuit connection of various components, but also consider various challenges brought by high speed and high density. PCB design will show the following trends:
1. The R & D cycle continues to shorten. PCB engineers need to use first-class EDA tool software; Pursue first board success, comprehensively consider various factors, and strive for one-time success; Multi person concurrent design, division of labor and cooperation; Reuse modules and pay attention to technology precipitation.
2. The signal rate increases continuously. PCB engineers need to master certain high-speed PCB design skills.
3. High veneer density. PCB engineers must keep up with the forefront of the industry, understand new materials and processes, and adopt first-class EDA software that can support high-density PCB design.
4. The working voltage of the gate circuit is getting lower and lower. Engineers need to clarify the power channel, not only to meet the needs of current carrying capacity, but also by adding and decoupling capacitors appropriately. If necessary, the power ground plane shall be adjacent and tightly coupled, so as to reduce the impedance of power ground plane and reduce the noise of power ground.
5. Si, PI and EMI problems tend to be complex. Engineers need to have basic skills in Si, PI and EMI design of high-speed PCB.
6. The use of new processes and materials, buried resistance and buried capacity will be promoted.
