With the increasing integration of various ESD circuits, the line width of integrated circuits is also reduced. Transient voltages in the circuit in the form of electrostatic discharge (ESD) or other forms are therefore more likely to cause damage to electronic devices. Various multi-functional mobile terminal devices are constantly emerging to meet people's increasing use needs, and the corresponding functional interfaces are also constantly being upgraded. The requirements are getting higher and higher, and the upgrade of the main chip puts forward more stringent requirements for port protection. ESD products with traditional structures can no longer meet customer application requirements.

Bidirectional large snapback SCR characteristics Low capacitance TVS has the characteristics of ultra-low residual voltage and ultra-low capacitance, mainly for ESD protection of high-speed data interfaces such as HMDI2.0 and USB3.0/3.1.

 The bidirectional TVS diode can discharge the surge pulse from the positive and negative ends of the data line, thereby protecting the system from various forms of transient high voltage shocks. Compared with ordinary bidirectional TVS, TVS with large snapback characteristics adopts SCR process (thyristor technology) to achieve the goal of ultra-low residual voltage during ESD and Surge tests. It is reduced to 1-3V to achieve the purpose of ultra-low residual voltage. It has a very reliable bidirectional overvoltage protection function in the actual application process, and has higher flexibility and reliability in EDS device protection applications.

The common bidirectional TVS is mostly NPN structure, and the equivalent circuit diagram is shown in Figure 1. The bidirectional TVS is doped with a layer of N-type impurities on the N-type silicon substrate/P-epitaxial to form an NPN junction. As shown in Figure 2, the ordinary bidirectional TVS includes an ALsicu metal layer 24, a SiO2 insulating layer 23, and an N-type doped layer. 22, P- epitaxy 21, N+ substrate 20. At present, the protection of many ports tends to be bidirectional protection, but ordinary bidirectional TVS can no longer meet the requirements of ultra-low residual voltage and ultra-low capacitance of high-speed data communication ports, so it is very urgent to develop bidirectional low residual voltage devices.