An integrated circuit includes a bi-directional signal transmission pin connected to a sensing electrode of a salinity sensor, an RF interface which generates operating voltages on the basis of an RF signal received through an antenna, different types of driving signal generators having a structure in which each output terminal is connected to the pin, different types of analog-to-digital converters having a structure in which each input terminal is connected to the pin, and a microcontroller unit which generates a first control signal and a second control signal according to a type of the salinity sensor, in which one of the different types of driving signal generators is enabled based on the first control signal, one of the different types of analog-to-digital converters is enabled based on the second control signal, and the operating voltages are supplied to an enabled signal generator and an enabled analog-to-digital converter.