The properly and electrostatically measured taping materials are used for the components, but attention should be paid to the fact that there is some danger the parts absorb on the top
tapes to cause a failure in the mounting and the parts are destructed by static electricity (more than 1kV : 1J, 2A, 2B, 2E 0.5kV : 1E, Human Body Model 100pF 1.5kΩ) to change the
resistance in the conditions of an excessive dryness or after the parts are given vibration for a long time as they are packaged on the tapes. Similarly, care should be given not to apply the
excessive static electricity when mounting on the boards.
●
Ionic impurities such as flux etc. that are attached to these products or those mounted onto a PCB, negatively affect their moisture resistance, corrosion resistance, etc. The flux may
contain ionic substances like chlorine, acid, etc. while perspiration and saliva include ionic impurities like sodium (Na
＋
), chrorine (Cl
−
) etc. Therefore these kinds of ionic substances may
induce electrical corrosion when they invade into the products. Either thorough washing or using RMA solder and flux are necessary since lead free solder contains ionic substances.
Washing process is needed, before putting on moisture proof material in order to prevent electrical corrosion.
●
Please pay attention that the top of an iron does not direct touch to the components. There is a risk that may cause a change in resistance. Take care that another risk may happen that
the protecting coat is carbonized in an instant when touched directly by the top of the iron, also climatic-proof for electric corrosion or insulation of protecting coat may be dropped down.
Be sure not to give high temperature on the top of the iron as it will degrade the protecting coat.
●
Avoid storing components under direct sun rays, high temperature/humidity. Direct sun rays will cause quality change of taping and difficulty of keeping appropriate peeling strength. 5∼
35℃/35∼75%RH, there is no deterioration of solderability for 12 months, but take special care for storing, because condensation, dust, and toxic gas like hydrogen sulfide, sulfurous acid
gas, hydrogen chloride, etc. may drop solderability.
This article discusses the PCB layout of a power supply circuit that generates a regulated 3.3 V rail from a small solar cell. My goal in this project was to create a very simple, very compact circuit...
1. The bq24650 output voltage is abnormal and cannot be chargedNow I have a problem. The connection of bq24650 is as shown in the figure. The setting is 6V input and 4.2V output. But if the input volt...
When starting a new design, most of the time is spent on circuit design and component selection, and the PCB layout and routing stage is often not considered carefully due to lack of experience.
Failu...
[i=s]This post was last edited by DavidZH on 2019-5-1 16:06[/i] As an electronics enthusiast, DIY is inevitable. As the saying goes, a good tool is a must. I have been paying attention to an ultrasoni...
Recently, Synopsys (Nasdaq: SNPS) released the "2021 Open Source Security and Risk Analysis" report (OSSRA). The report was produced by the Synopsys Cybersecurity Research Center (CyRC) and studied t...[Details]
I. Overview Regardless of the microcontroller, if you want to control the LED light, you can only do so by controlling the level of the I/O pin of the microcontroller chip. Similarly, on ST microcont...[Details]
The STM8L152XX series has an on-chip segment LCD driver, which provides a guarantee for low-cost applications and high-density system design. By using the on-chip LCD driver module, the overall po...[Details]
introduction
A long-standing challenge for designers of MP3 players, personal media players, digital cameras, and other portable consumer applications is to achieve high performance and low pow...[Details]
During the three key periods of the Ninth Five-Year Plan, the Tenth Five-Year Plan, and the Eleventh Five-Year Plan, my country spent billions of yuan to build a national digital seismic network an...[Details]
NI proposed the concept of virtual instruments in the 1970s. Virtual instruments are computer instrument systems designed by users on a computer-based platform, with virtual panels and software to im...[Details]
Many years ago, I was proud of the tens of thousands of lines of assembly code I had written. However, as someone who has been engaged in software development for many years, I still don’t understa...[Details]
Solution Overview This solution uses Sunplus's SPHE 6700 as the main chip of the solution. SPHE 6700 is a highly integrated automotive SoC for ADAS (Advanced Driver Assistance System) applications....[Details]
STM8S103K3: External clock + internal clock switching. First, take a look at the clock structure diagram of STM8S103K3, which can help you understand it well. There are several clocks here, whic...[Details]
According to foreign media SamMobile, a running score information of the Samsung Galaxy S21 Ultra 5G mobile phone appeared on the Geekbench 5 website. It is worth noting that the phone runs th...[Details]
1. Hibernation operation Just execute asm("SLEEP"); or SLEEP; 2 GPIO status after sleep Keep GPIO status after sleep 3 Where does the program start executing after waking up? Generally, MCL...[Details]
The market share of electric vehicles will reach 50% in 2030, and the electrification process of the automobile industry will accelerate. A bright future for electric vehicles is coming as global a...[Details]
On the evening of the 21st, Unigroup Guoxin (SZ002049) released its 2020 performance report. During the reporting period, it achieved revenue of 3.27 billion yuan, excluding the impact of changes in ...[Details]
Shanghai, China, November 4, 2024 -
Farnell element14, a global distributor of electronic components products and solutions under Avnet, announced a comprehensive expansion of its tool and prod...[Details]
PCB Design
京公网安备 11010802033920号
EEWORLD
