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.
空分复用 (SDM) MIMO 处理可显著提高频谱效率，进而大幅增加无线通信系统的容量。空分复用 MIMO 通信系统作为一种能够大幅提升无线系统容量和连接可靠性的手段，近来吸引了人们的广泛关注。 MIMO 无线系统最佳硬判决检测方式是最大似然 (ML) 检测器。ML 检测因为比特误码率 (BER)性能出众，非常受欢迎。不过，直接实施的复杂性会随着天线和调制方案的增加呈指数级增强，使...[详细]
stm32/stm8
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