A study on electrical stress induced by electrostatic discharge on wearable devices

In recent years, wearable devices such as smartphones are widely used. However, in real environment wearable devices are used, ESD occurrence conditions are considered to be different from previous test methods because wearable devices are usually held by users in their body. In this study, we measured electrical stress induced by ESD from a charged human's fingertip to grounded objects on wearable devices held in charged human. From experimental results, shapes of the induced voltage waveforms, their durations, and amplitudes are quite different between each antenna. Especially, the durations of the induced voltage waveforms are changed between ten nanosecond order and hundred microsecond order. This means that electrical stress induced by ESD on wearable devices is very various and it depends on circuit structure.