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3rd Generation Technology Moisture Immunity

We will now Discuss a bit further the improved moisture immunity performance. This feature is achieved by designing a shield electrode that surrounds the sensing electrodes. This shield drive electrode is driven by the output feedback of the Cap-touch sensing electrode. This driver source is switched between the different capacitive sense electrodes as they are periodically scanned. This way, when water droplets fall on the surface, the capacitance impact of it will be zeroed out, and only the additional capacitance of the finger touch will be used. Implementing this solution requires using one pin for the shield driver, and have to properly take into considerations preventing limitation such as increased power consumption and impact of RF emissions.