Overvoltage protection for computer serial communication

Micro-electronic circuits are often damaged by overvoltage. Shunting current, equalizing voltage, grounding, shielding and surge suppression are effective countermeasures for overvoltage protection, but overvoltage protection for micro-electronic circuits has some special demands different from these for electrical equipment. The approach that the overvoltage invades into micro-electronic circuits is studied in this paper. Based on the experimental results of the overvoltage withstand capability of some typical serial communication integrated chips, the experiments of the influence on digital signals caused by the connecting capacity of the voltage clamping device, and the experiments of voltage limiting components' behavior, a design method of overvoltage protector for computer serial communication is proposed.