What should I pay attention to when TVS diodes (ESD protection diodes) do not work properly?

If the IC to be protected is destroyed by static electricity even in the presence of ESD protection devices, ESD protection performance is insufficient for this IC. Care should be exercised especially when the IC to be protected has low ESD immunity.

The following figure compares the first peak voltage at the input of the IC following the replacement of two different TVS diodes. Although being similar in functionality, these TVS diodes exhibit different clamp voltages. (DF2B5M5SL: 9.6 V typical at 4 A; competitor’s TVS diode: 13 V typical at 4 A). This figure indicates that the DF2B5M5SL provides more robust protection against ESD pulses. Note that even similar TVS diodes exhibit considerably different ESD protection performance.

It is important to select the optimum TVS diode according to the application requirements.