Selection knowledge of ESD static diodes and TVS tubes

When we encounter ESD (electrostatic discharge) issues, we usually add ESD static diodes or TVS (transient voltage suppressor) static protection diodes to the sensitive circuits or the paths of external signals to discharge the ESD. However, there are also times when engineers are choosing ESD suppressors and TVS tubes, and they may not be clear about some of their parameters. As a result, they sometimes cannot quickly select the appropriate protective devices.

ESD suppressors are made of polymer (POLYMER) voltage-induced materials and high electrical molecular material cores. We call them polymer ESD. Their characteristics include no limit on the lifespan of physical discharge, reaction speed < 1ns, ultra-low capacitance (< 0.15pF), and ultra-low leakage current (< 1nA). Their main parameters are:

1. Reverse Stand-off Voltage: Vr represents the reverse voltage, which is the voltage at which conduction does not occur. At this voltage, there is only a very small reverse leakage current. For example, if this TVS diode is connected to an IC pin, when selecting it, it is sufficient if the operating voltage of the IC is lower than this voltage.

2. Breakdown Voltage: The breakdown voltage. It is the voltage at which the TVS diode passes the specified test current IT.

3. Maximum Clamping Voltage: The maximum clamping voltage. It is the voltage across the TVS diode when it passes the maximum peak current Ipp.

4. Maximum Peak Pulse Current: The maximum peak current that the TVS diode can handle during a 10/1000μs pulse. Exceeding this current will damage the TVS diode.

5. Maximum Reverse Leakage: The maximum reverse leakage current. It is the leakage current of the TVS diode under reverse voltage. The smaller this parameter is, the better.