ESD Protection Devices (anti-static components)Section 1　“What are ESD (Electrostatic Discharge) countermeasures?”

When two electrically charged objects, such as the human body and an electronic device come into contact with each other, static electricity is discharged. This phenomenon is called ESD (Electrostatic Discharge). ESD generated from the human body can be of the order of several thousand volts. This high voltage pulse enters the electronic device that is touched, resulting in a malfunction or destruction of the IC circuits inside it. In order to prevent the destruction of a product or system due to the intrusion of ESD into an electronic device that was touched, it is necessary to install countermeasure components that suppress or remove ESD.

As stated previously, ESD is a discharge phenomenon of static electricity that occurs when a charged conductive object touches or draws sufficiently close to another conductive object.

On the other hand, surge is a general term used to refer to transient excessive voltage or excessive current.
Excessive currents that occur when the switch is ON/OFF is called "surge" and excessive voltages and excessive currents that occur due to lightning is called "lightning surge."

ESD countermeasures are necessary at all points where electrical devices are likely to come into contact with a person or an object. Examples include USB2.0, USB3.0, output terminals, LAN, various I/O interfaces or other points where a user connects or disconnects a connector, cases in which an operation button of an electrical product is touched, or a device touches a board during a production process, and also cases in which boards are connected to each other using a connector. Parts that are installed at these points as ESD countermeasures are called “ESD protection suppressors*.”

TVS diodes, suppressors, varistors, and arresters are ESD protection elements. Murata provides a range of TVS diodes.
TVS diodes are used to protect against transient excessive voltage caused by static electricity (ESD).
They are suitable for protecting data terminals (such as on USB devices) and power terminals. (See here for a usage example)
Section 3 "TVS Diodes? (ESD Protection Devices)" provides a detailed explanation of the differences between TVS diodes, varistors, and suppressors.

As shown on the figure on the left, ESD enters a device from its external interface, which can easily be touched by hand.
Without an ESD Protection Element, excessive voltage of several thousands of volts (such as ESD) could be applied directly to the IC over the external interface, damaging the IC. ESD Protection Elements protect ICs from being damaged by ESD. As shown in the figure on the right, they are connected between the data line and ground, between the external interface and IC.
In order to provide protection, an ESD Protection Element needs to provide two functions:

TVS diodes have either low or high capacitance, and high-electrostatic discharge capability.
They are capable of absorbing a high amount of static electricity on DC data lines up to 5 Gbps.
Murata provides various sizes of products, from 0402 to 1,006 mm.
Section 3 "TVS Diodes? (ESD Protection Devices)" provides a detailed explanation of the differences between TVS diodes, varistors, and suppressors.