An integrated passive radio frequency identification transponder chip includes a backscatter modulator for communication with a backscattering principle, a tag oscillator generating a backscattering modulation frequency, and a reference load, preferably a reference resonator. Either the reference load or at least one pair of an internal or external resonator and an external sensor element can be selectively connected to load the tag oscillator. Each external sensing element is arranged to sense a predetermined variable. The tag oscillator is capable of generating any one of nominal backscattering modulation frequencies defined for a respective RFID system, when the reference load is connected to load the tag oscillator. The tag oscillator is arranged to generate a predetermined one of nominal backscattering modulation frequencies, when the at least one pair of the internal or external resonator and the external sensor element is connected to load the tag oscillator.