Here you'll find insights into PCB design, tech trends, assembly issues, and trending topics
in the general news media as they relate to printed circuit board technology.
As experts in the manufacture and assembly of printed circuit boards, we work to make our blog a helpful resource on PCB topics and the industries that we work with, including automotive, consumer electronics, aerospace and many more.
Modern digital circuits can be up to GHz and rise time is within 50ps. At such a rate, the negligence on the PCB design trace is even one foot, and the resulting voltage, delay and interface problems will not only be limited to this line, but will also affect the entire board and Adjacent boards.
Radiated EMI interference can come from an undirected source and an unintentional antenna. Conductive EMI interference can also come from a source of radiated EMI interference or caused by some board components. Once your board receives conductive interference, it resides in the PCB trace of the application circuit. Some common sources of radiated EMI interference include the components discussed in previous articles, as well as on-board switching power supplies, cables and switches, or clock networks.
How to define differential pairs in the schematic
Many people think that the work of PCB Layout is very boring. Every day, thousands of wires are routed to the board, and various packages are repeated, and the work of pulling the wires is repeated. However, designers must make trade-offs between various design rules, taking into account performance, cost, process and other aspects, but also notice that the layout of the board is neat and tidy, not as simple as it seems, and requires more wisdom. Let's talk about developing some good work habits during design, which will make your design more reasonable, easier to produce, and better.
The main parasitic components generated by board layout are resistors, capacitors, and inductors. When switching from a circuit diagram to an actual board, all parasitic components have a chance to interfere with circuit performance. When a system mixes digital and analog components, careful routing is key to the success of the board. In particular, digital traces that are often close to high-impedance analog traces will cause severe coupling noise, which can only be avoided by keeping the two traces at a distance. This article quantifies the toughest board parasitic components, board capacitors, and lists the performance examples that can be clearly seen on the board.
Which method do you know below to reduce noise and electromagnetic interference in PCB design?
This article uses Protel99 SE as a design tool to analyze and discuss the basic principles and experience and skills in PCB design.
Although the high-speed simulation tools and interconnect tools at this stage can help designers solve some of the problems, high-speed PCB design also requires the accumulation of experience and in-depth communication between the industry.
The via design consists of a pad and a pad area around the hole and an inner electrically isolated area. The parasitic inductance, parasitic capacitance, etc. of the vias affect the high-speed signals passing through the vias. The size of the vias and the pads connected to them have a direct effect on the properties of the vias.
Printed circuit board design is another important part of Protel 98. In this process, you can use the powerful functions provided by protel98/protel99se to realize the layout design of the board and complete the difficult wiring work.
1. Impedance matching refers to the proper matching between the signal source or transmission line and the load. According to the access mode, there are two modes of impedance matching: serial and parallel; according to the source frequency impedance matching, it can be divided into low frequency and high frequency.
PCB design techniques have an impact on the following three effects:
In high-speed designs, the characteristic impedance of the controllable impedance plates and lines is one of the most important and common problems. First, let's look at the definition of a transmission line: a transmission line consists of two conductors of a certain length, one for transmitting signals and the other for receiving signals (remember that the "loop" replaces the concept of "ground"). In a multi-layer board, each line is part of the transmission line and the adjacent reference plane can be used as a second line or loop. The key to a line becoming a "perfect" transmission line is to keep its characteristic impedance constant throughout the line.
The design performance of multi-layer boards is mostly similar to single-panel or double-panel, which is to avoid avoiding too many circuits to fill too small space, resulting in impractical tolerances, high inner layer capacity, and possibly even dangerous products. Quality safety. Therefore, the performance specification should consider the complete evaluation of the thermal shock, insulation resistance, welding resistance, etc. of the inner layer. The following sections describe important factors that should be considered in the design of multilayer boards.
One of the main purposes of the design of the circuit schematic is to provide a network table for the design of the PCB board and to prepare the basis for the design of the pcb board.
In the design of the PCB, in fact, before the formal wiring, it has to go through a very long step, the following is the main design process:
The PCB manufacturing process begins with a "substrate" made of Glass Epoxy or similar material.