Because conventional SD cards are frequently inserted and removed components, it is difficult to avoid contact with ESD sources. In order to prevent the SIM card from dropping under strong interference, ESD protection devices are required to avoid working near the limits of design parameters, and it is necessary to avoid contact with ESD sources. To protect the circuit and the possible ESD impact, select a device with a fast enough response speed and a sufficiently high sensitivity, which is very important for the effective play of the role of the protection device. Another reason