Research On ESD Protection Devices

A number of sensitive electronic equipment is weak in withstanding high voltageor high current. The application of off chip ESD protection devices can significantlyenhance the protective effect. The ESD protection devices will directly affect thenormal operation of the equipment, so it is important to carry out a research in ESDprotection device under the electromagnetic pulses. At present, there is hardly everany study in each protective device in the response to ESD. But ESD is precisely themain source of electromagnetic hazards to the electronic equipment. The main resultswere as follows:Test and analysis of single ESD protection device are carried out. Choosedifferent types of TVS, varistor, gas discharge tube under different discharge voltage,and the results show that under different discharge voltages, the clamping voltages ofTVS, varistor differ slightly, the higher the test voltage, the higher clamping voltage.At the same time, the response time becomes longer, and the peak voltage, peakcurrent increase. The peak response voltage increases along with the test voltage, sodoes the peak response current. The clamping voltage basically remains unchanged,and the response time of the gas discharge tube decreases. Finally this papersummarizes the advantages and disadvantages of different ESD protection devicesand evaluates the ESD protection device.Test and analysis of ESD protection network are carried out. Choose the samedevice, the same kind of different version, and different kind of devices to build aprotection network. And the contact discharge test is carried out, and thecharacteristics are analyzed. When TVS and varistor are in series, the clampingvoltage increases as the sum of the two, but the response current reduced. When thesame TVS are in parallel, the response voltage changes little, but the response currentincreases. As the parallel number increases, the response current increases. But it isnot proportional with the parallel number. When the same varistors are in parallel, theresponse voltage reduces with the number of parallel but the clamping voltage hardlychanges. As the parallel number increases, the response current increases. But it is notproportional with the parallel number. Damages may happen when different types ofdevices are in parallel. In the practical application of electrostatic discharge up tothousands of volts, we can use more TVS or varistor in the same version in series for safe. In the condition of larger current flow for a invariable clamping voltage, thepriority solution is the multiple parallel TVS or varistors in the same version.