Principle of ESD protection diode

ESD discharge diode is an overvoltage and anti-static protection component designed for I/O port protection in high-speed data transmission applications. ESD protection devices are used to prevent sensitive circuits in electronic devices from being affected by ESD (electrostatic discharge).

ESD is a discipline that has emerged since the mid-20th century to study the generation and decay of static electricity, static discharge models, static discharge effects such as current thermal (spark) effects (such as ignition and explosion caused by static electricity), and electromagnetic effects (such as electromagnetic interference). In recent years, with the rapid development of science and technology, the widespread application of microelectronics technology, and the increasingly complex electromagnetic environment, the electromagnetic effects of electrostatic discharge, such as electromagnetic interference (EMI) and electromagnetic compatibility (EMC), have become increasingly important.

ESD electrostatic protection has two types of components, one is silicon-based material and the other is polymer material! The working principle is different! The principle of silicon-based materials is similar to that of TVS diodes! Clamp the high voltage first, and then discharge to the ground!

The most critical reference coefficients for protective devices such as ESD static diodes, ESD static protectors, and ESD protective diodes are as follows:

1. Fast response time

2. Low clamping voltage

3. High voltage stray surge bearing capacity

ESD diode principle: The ESD electrostatic protection diode is connected in parallel to the circuit. When the circuit is working normally, it is in a cut-off state (high resistance state), which does not affect the normal operation of the circuit. When the circuit experiences abnormal overvoltage and reaches its breakdown voltage, it quickly changes from a high resistance state to a low resistance state, providing a low impedance conduction path for instantaneous current and clamping the abnormal high voltage within a safe level, thereby protecting the protected IC or circuit; When the abnormal overvoltage disappears, it returns to the high impedance state and the circuit works normally.

When the voltage exceeds the conduction voltage of the diode, it will conduct and discharge through grounding. Normal signals generally cannot reach the conduction voltage and will not reach this voltage, so there will be no ground loss. On the other hand, when the ESD voltage exceeds the conduction voltage, the diode will conduct and the ESD voltage will discharge through grounding, without damaging the inside of the instrument.