There are many kinds of PCB design software, and the main market uses include: Cadence, Allegro, Mentor, EE, Mentor, Pads, Altium, Designer, Protel and so on. Among them, the market share of Cadence Allegro is the highest.
1, the mainstream PCB design software features:
(1) function integration: complete design platform, including schematic design, PCB design, circuit simulation analysis and other functions;
(2) functional components: different functions are implemented in different software module components, and users can selectively purchase and install;
(3) circuit analysis is powerful: to meet the current high-speed development trend of PCB, to determine the design rules by simulation, to design rules driven PCB design implementation;
(4) support team work: you can do module partitioning for PCB, collaborative design on line or off line mode
PCB design software using the same approach, basically based on the PCB design process, the convergence of functional modules, but the specific software menu or design order of operation is different.
2, high-speed PCB design principle
First of all, what is "high speed"?
Generally speaking, the traditional circuit theory is applicable to the circuit analysis of the circuit size of signal interconnection which is much smaller than the corresponding wavelength of the highest frequency concerned by the designers in the transmission signal. At this time, the signal is equivalent to a first-order circuit interconnection element, known as the "lumped element" (Lumped Elements); on the contrary, when the size of the signal interconnection circuit corresponding to the highest frequency close to the designer more concerned about the transmission signal in wavelength, due to the size and phase of interconnect paths on different positions of the voltage or current of all may be different, the signal interconnection is equivalent to multi order circuit components, so it is called the "distributed element" (Distributed Elements).
The above is the "signal integrity theory for signal transmission behavior of PCB interconnection line understanding, signal edge rate almost completely determines the maximum frequency components in the signal, usually when the interconnect transmission delay signal edge time is less than 4~6 times under the condition that the signal interconnection path would be regarded as a distributed parameter model, need to consider the" signal integrity "behavior.
The so-called "high speed" means "interconnection delay" signal edge time is less than 4~6 times, we can see that the signal circuit board transmission is "high speed", not only the edge rate depends on the signal path length, but also depends on the size of printed circuit board, when there is a certain proportional relationship between them, the signal should be in accordance with the "high speed signal processing.
The principle of high speed PCB design comes from the theory of signal integrity. Students can refer to relevant materials and documents for study. High speed PCB design is now fully supported by the PCB design software tools, and the design and implementation of PCB design rules are implemented in the PCB design software tool function.
3, PCB design needs to master knowledge
3.1 demand class knowledge
Circuit principle, signal integrity, power integrity, structure, power supply, thermal design, electromagnetic compatibility, machinability, testability and so on
3.2 basic knowledge
(1) design software installation and basic operation
(2) basic knowledge of printed circuit board manufacturing (processing, processing, material, etc.)
(3) basic usage of hardware schematic tools (functional modules related to PCB design)
The above is about the mainstream PCB design software features introduced and need to master the basic knowledge of PCB design, I hope for the beginner PCB design engineers have a general help.
