What should I consider when selecting TVS diodes (ESD protection diodes) for high-speed signal lines?

A simplified equivalent circuit of the TVS diode

You need to consider the normal operating state in which a circuit is not being exposed to  static electricity and other excessive voltage  (in this state, the TVS diode is off).
A simplified equivalent circuit of the TVS diode is shown below. When the TVS diode is off, the TVS diode acts in the same way as a capacitor by junction capacitance. This capacity is called the total capacitance CT. Since this capacitance is placed between a signal line (data path) and GND, the signal integrity of a high-speed signal is subject to degradation. To maintain signal integrity, it is necessary to select TVS diodes with adequate total capacitance CT.

figure as a guide when selecting TVS diodes

Use the following figure as a guide when selecting TVS diodes.

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