ESD Current Spread Measurement Using Mesh Structure

If a PCB is struck by an ESD the injected current spreads throughout the PCB and returns via attached cables. During the current spread a variety of effects occur: The current spreads on the main ground and power planes, couples into traces and IC lead-frames and bond wires. Further, the PCB and the attached cables can form resonators causing ringing at their natural resonance frequencies. Understanding the current spread onto a PCB, best, also onto the traces is of great importance for gaining insight into ESD related problems on products. A test setup has been created that allows capturing and quantifying the spreading current. It is a mesh like structure above a ground plane. The current in each trace of the mesh can be measured via the magnetic field allowing to analyze the magnitude of the current for complete mesh or slotted mesh structures. Additionally, Current-probe was designed though the process of measuring the current waveform.