Working principle of ESD​ diode

Working principle of ESD diode

When the system has no abnormal interference and operates normally, the ESD electrostatic protection diode can be ignored and has no effect. But when the external interface voltage exceeds the breakdown voltage of the  ESD diode, the  ESD diode begins to function and diverts the current to ground.

There are three types of  ESD diode models, namely, Mannequin (HBM) ESD (designed for chip production, assembly, and transportation), Charged Device Model (CDM) ESD (designed for chip production, assembly, and transportation), and IEC61000-4-2 ESD (designed for daily use). Among them, IEC61000-4-2 level is the daily contact level, and under normal circumstances, it is divided into four levels:

Level 1: Contact discharge voltage 2KV, air discharge voltage 2KV

Level 2: Contact discharge voltage 4KV, air discharge voltage 4KV

Level 3: Contact discharge voltage 6KV, air discharge voltage 8KV

Level 4: Contact discharge voltage 8KV, air discharge voltage 15KV