Electrostatic discharge (ESD) can occur on electrically insulated objects, such as a person being charged due to friction and sudden discharge when touching a grounded metal object. The electrostatic potential can be as high as 30 kV, and the resulting discharge is very short, usually 100 ns, and the peak current can be as high as 100 A. The harm caused by electrostatic discharge should not be underestimated. For example, when a car is driving, static electricity enters the electronic equipment through the contact between the human body and the electronic equipment of the car. Even the slightest pulse can damage the sensitive electronics in these systems. This causes damage to the equipment circuit and even affects the driving safety of the car.

In order to inherit more functions of many automotive electronics, the chip integration is getting higher and higher, and the physical size is reduced by reducing the geometric size of the silicon process. The last point is the key to the level of ESD existence-industry trends have tended to adopt smaller process sets, and chipsets are more sensitive to ESD. Designing powerful automotive electronics requires advance planning for the management of a large number of environmental and electrical hazards that exist in the automotive environment. Therefore, the following basic requirements should be met when selecting ESD protection devices:

TVS is a common ESD protection device. The basic requirements for TVS are related to specific applications, but in general, there are the following requirements: (1) It can work normally under the expected ESD stress; (2) It has high impedance within the normal voltage range (Low leakage); (3) Low impedance outside the normal voltage range; (4) The on-voltage is suitable for application; (5) It can quickly switch from high impedance to low impedance during stress period. (6) Capacitor to target Application is not too high.