Hi TI Team,
According to the reference design of the FDC1004DGS water level sensor, we have made several prototypes. The PCB design drawing is shown in the attachment (FR4, thickness 1.6mm). The water level test height is 25cm. There is a problem during the test. When the water level is empty, the capacitance is measured. It is almost close to 10pf. After the water level is added to 12cm, the capacitance will not increase after reaching the maximum value of 15.99pf. Can you help analyze or ask what could be caused by the excessive capacitance of the original TI when the water level is empty, and what is there? No suggestions for improvement, thank you.