The anti-static diode is parallel to the protected line on the circuit board. When the instantaneous voltage exceeds the normal working voltage of the circuit, the anti-static diode will avalanche, providing an ultra low resistance path for the instantaneous current. The result is the instantaneous current through the diode is away, away from the protected device and restore the normal value before the protected circuit has been cut-off voltage in voltage. When the instantaneous pulse is over, the antistatic diode automatically reverts to the high resistance state, and the whole loop enters the normal voltage.

1. Determine the maximum DC or continuous working voltage of the protected circuit, the rated voltage of the circuit and the "high end" tolerance.
2. The rated reverse turn off VWM of the antistatic diode should be greater than or equal to the maximum working voltage of the protected circuit. If the selected VWM is too low, the device may enter the avalanche or the reverse leakage current is too large to affect the normal operation of the circuit. The serial connection is divided into voltage, parallel connection and current division.
3. The maximum clamping voltage of the antistatic diode (VC) should be less than the damaged voltage of the protected circuit.
4, in the specified pulse duration, the maximum peak power consumption PM of the electrostatic diode must be greater than that of the peak power that may appear in the protected circuit. After determining the maximum clamping voltage, the peak pulse current should be larger than the transient surge current.
5. For the protection of the data interface circuit, we must also pay attention to the selection of an anti static diode device with a suitable capacitance C.
6. The polarity and encapsulation structure of antistatic diode is selected according to its use. The use of bipolar antistatic diode in AC circuit is more reasonable; multi line protection is more favorable for selecting antistatic diode array.
7. The temperature is considered. Transient voltage suppressor can work in 55~+150 c.. If you need antistantic diode in a changing temperature, due to the reverse leakage current of ID is increased with the increase of power consumption; decreased with antistantic diode junction temperature increases from +25 DEG to +175 DEG, approximately linear decrease 50% rain breakdown voltage VBR with the increase of temperature in a certain coefficient increases. Therefore, the relevant product information must be consulted and the effect of temperature change on its characteristics must be considered.
Antistatic diodes can be divided into unidirectional antistatic diodes and bi-directional antistatic diodes, unidirectional positive and negative poles, and no positive and negative poles. Antistatic diodes are widely used in the protection of semiconductors and sensitive parts, the protection of two level power and signal circuits, and anti static electricity.