Why is ESD protection so important for integrated circuits? How to protect?

All siege Lions , Before talking about dry goods today , Let's test everyone first ：PCB Do you know this logo on ？

EDA365 Electronic forum

1

In fact! , It is PCB A kind of ESD Protective design , It's called spark gap . The spark gap consists of two electrodes separated by air , When the voltage applied between the electrodes exceeds the breakdown level , Gas ionization rapidly reduces the resistance between electrodes and discharges .

The breakdown voltage can be calculated by formula ：

V=3000*p*d+1350

p Is the pressure in the atmosphere ,d It's distance

Compared with the spark gap of semicircular gasket , Diamond discharge teeth are more common , But this kind of design often produces carbon deposition on two triangular points due to discharge , Finally, it will cause permanent short circuit of the signal line , And then cause system failure .

And the semicircular cushion design , Relatively speaking, it can provide repeated protection , Although this design can only occasionally ESD Used in , But because it costs nothing , So it is still very practical .

EDA365 Electronic forum

2

About ESD There are many protective measures ,pcb The design of spark gap is just one of them .

Although the static electricity in life has no great influence on us , But for many sensitive electronic components , But it has a very serious destructive impact .

ESD That is, electrostatic discharge is the main cause of component breakdown hazards and interference to the operation of electronic equipment .

Electrostatic discharge sensitive devices are called ESDS device , As devices become smaller and smaller , These devices are becoming more and more sensitive to electrostatic discharge .

A very thin conductive path on an integrated circuit , It is usually unable to withstand the high electrostatic discharge voltage involved , There are usually two kinds of damage , Direct damage and potential damage .

Less than 30% Direct damage , The device is seriously damaged , Loss of function , This kind of damage can be found in the quality inspection of the production process .

Therefore, the cost of rework and maintenance is mainly brought to the factory , And the vast majority of ESD Damage is potential damage , Part of the device is damaged , But the function has not been lost , And cannot be found in the inspection of the production process , Only when running can faults occur , Thus, there will be serious consequences , Therefore, the harm caused by potential damage is greater .

The best way to avoid or reduce this loss , Is to take electrostatic protection measures . In the process of production , The common ones are electrostatic bracelets and anti-static workbench , Their basic principle is to discharge static electricity to the ground plane through cables .

EDA365 Electronic forum

3

In addition to the electrostatic bracelet and anti-static workbench and spark gap ,ESD Protection is also a very important part , That is component selection .

The most common way to design circuits is to use TVS diode , Can handle lightning and ESD Caused by high transient current , But for the microwave signal of RF antenna , If you use TVS tube , Pressure sensitive and capacitive devices are used for electrostatic protection , The RF signal will be weakened , Therefore, corresponding measures should be taken for electrostatic protection according to the actual situation .

The above introduces three ESD Protection methods , I believe that if these three methods are used reasonably , Then our products will largely avoid electrostatic damage , So as to save cost .