Does the ESD protection device have to be placed close to the connector? Why is this? Can someone please explain this to me?

小太阳yy

Does the ESD protection device have to be placed close to the connector? Why is this? Can someone please explain this to me? [Copy link]

Does the ESD protection device have to be placed close to the connector? Why is this? Can someone please explain this to me?

Lower the series inductance? Is that correct?

annysky2012

I would like to share an article with you, which may answer your question. Practical experience: ESD protection circuit design of PCB board https://zhuanlan.zhihu.com/p/364515011

machinnneee

There is actually no standard way to say this, but in summary it is to reduce interference to the signal.

Placed close to the connector, it can protect the back-end circuit to the maximum extent

If it is close to the back end, it actually makes sense to unload the energy before entering the back end circuit. Generally, if there is a connector, it is placed at the connector. This is a common practice.

langtuodianzi

ESD protection devices should be placed at the connector or port to effectively suppress the occurrence of ESD events before ESD enters the circuit board.

Jack315

ESD protection refers to protecting circuit boards from damage due to static electricity.

There are two main ways that static electricity enters circuit boards:

① Through the connector on the chassis or housing, this type of static electricity entry is usually called contact discharge;

② This type of static electricity entering through gaps in the chassis or casing is usually called air discharge.

For contact discharge, the protection method is to set ESD devices on each pin of the connector.

Obviously, the ESD device should be as close to the connector pins as possible.

In this way, the energy is mainly absorbed by the ESD device, thus protecting the circuit board.

For air discharge, the function of electrostatic protection is mainly achieved through structural design.

An empirical data is that a path length of 1cm corresponds to 1 KV.

For example, for a 4 KV air discharge, the voltage across a gap in the (insulating plastic) chassis or housing is

The path length to the PCB must be at least 4 cm.

There are also some ESD protection measures for PCB routing...I won’t go into details here.

langtuodianzi

Electrostatic shielding of sensitive devices and external ESD protection devices are common methods for dealing with ESD testing.

chunyang

The specific situation must be analyzed. For ESD protection of external cable coupling, it is obvious that the protection components should be arranged near the external cable access point. This is done to suppress external dangerous factors as early as possible. Similarly, some external electrical interfaces may directly touch the human body. In this case, ESD suppression components should also be arranged nearby for the same reason. If the source of the ESD signal may be internal or introduced through non-specific access points, then the ESD suppression components may need to be arranged near sensitive circuits/components, but the specific situation still needs to be analyzed before the final judgment can be made.

Fred_1977

If it is an interface, it should be placed near the interface. There are two principles for EMC treatment. One is diversion, which means diversion. ESD and capacitors use diversion methods; the other is blocking, which means reducing the energy flowing downward. For example, when it rains heavily, in order to prevent the reservoir from collapsing, water is released on the one hand and dams are built on the other. This is what it means.

小太阳yy

Fred_1977 posted on 2021-12-28 19:43 If it is an interface, it should be placed close to the interface. There are two principles for EMC treatment. One is sparseness, which means shunting. ESD, capacitors are used...

Your metaphor is very vivid.