Basic selection principles for TVS diode protection

What principles should be paid attention to when selecting TVS diodes? This depends on the specific protection work of the TVS diode circuit diagram.
Electrostatic discharge (ESD) poses great harm to products, and TVS diodes are precisely used for port protection to prevent damage to the downstream circuit caused by momentary voltage surges at the port. TVS diodes can be classified as unidirectional or bidirectional,
Unidirectional TVS is generally used in DC power supply circuits, while bidirectional TVS is used in AC power supply circuits.
TVS diode protection operation mode
TVS is connected in parallel to the line for instantaneous surge suppression. Under normal working conditions, TVS presents a high impedance state to the protected device, which does not affect the normal operation of the circuit. When there is an abnormal overvoltage pulse exceeding its breakdown voltage, TVS switches from high impedance to high impedance
The impedance state changes to a low impedance state, providing a low impedance path that diverts the instantaneous current flowing to the protected component to the TVS diode. The instantaneous surge current is discharged through the TVS diode, while accurately limiting the voltage to a safe level
When the abnormal overvoltage disappears, the TVS immediately returns to a high impedance state.
TVS diodes operate in a voltage reverse breakdown state. When the reverse voltage reaches and exceeds the stable voltage, the reverse current suddenly increases while the voltage across the diode remains constant. Under the specified reverse application conditions, when subjected to a high-energy transient
When pulsed, its working impedance can immediately drop to a very low conduction value, allowing large currents to pass through and clamping the voltage to a predetermined level, effectively protecting precision components in electronic circuits from damage. Fast response speed (pS level), small size, low clamping voltage, high reliability. Bidirectional TVS is suitable for AC circuits, while unidirectional TVS is generally used for DC circuits.