Category Archives: Uncategorized

When I once saw the PCB of the computer motherboard, I thought how great it was to draw it myself. Later, when I came into contact with protel99se, I stepped into the team of drawing boards, and then altium, cadence and so on. With the accumulation of experience in drawing boards, more and more matters […]

PCB via problem phenomenon description During the trial production of the new intelligent conference equipment samples produced by circuit R&D, when the samples were subjected to strict aging test and the system performance test, it was found that two devices were disconnected (abnormal communication), accounting for 4% of the total tested products. After analysis, it […]

Differential current and common-mode current Radiation Generation: Current causes radiation, not voltage. Static charge generates electrostatic field, constant current generates magnetic field, and time-varying current generates both electric field and magnetic field. There are common-mode current and differential-mode current in any circuit. The differential-mode signal carries data or useful signals, and the common-mode signal is […]

Some STM32 application customers who use external SDRAM reflect that in EMC test, the radiation interference caused by SDRAM signal exceeds the standard. If the chassis can’t shield the radiation interference in the terminal products, then this kind of problem often needs to be solved by modifying the PCB design of SDRAM signal. Here, how […]

No.1 data input stage Whether the information received in the process is complete (including: schematic diagram, *.brd file, bill of materials, PCB design specification, PCB design or change requirements, standardization requirements specification, process design specification and other documents). Make sure the PCB template is up to date. Whether the clock layout is reasonable. Confirm that […]

When PCB is to be processed by SMT, PCB is transported by guide rail on SMT production line. Therefore, a pair of edges of forbidden cloth elements must be reserved as transport edges. Usually, the two long sides of the PCB or the rear panel of the jigsaw puzzle are used as its conveying edges. […]

With the pitch of ball grid array package (BGA) decreasing from 1.0mm to 0.8mm, 0.4mm or even smaller, the technological development of component packaging industry is obvious. At the same time, it becomes more and more difficult to fan out and route the dense circuits related to these components. At present, high-density interconnect (HDI) method […]

1.PCB VS flexible printed circuit board PCB is one of the important electronic components in the electronic industry. Almost every kind of electronic equipment, such as electronic watches, calculators, computers, communication electronic equipment, military weapon systems, etc., as long as there are electronic components such as integrated circuits, all need to use printed boards for […]

This is one of the qualitative design rules of RF analog PCB and one of the EMC design rules of high-speed PCB. Qualitative but not quantitative, I have no idea. Make a quantitative conclusion with HFSS today. Some junior engineers violate this rule, which leads to the deterioration of the whole board index. It is […]

1. Ground wire layout: 1. Digital ground is separated from analog ground. 2. The grounding wire should be as thick as possible, so that it can pass at least 3 times the allowable current on the printed circuit board, generally 2~3mm. 3. The ground wire should constitute an infinite loop as far as possible, so […]