A tunable differential active inductor and a switched bandpass amplifier in CMOS technology are presented. The active inductor is implemented in a 0;25 ¬Ķm CMOS technology at a supply voltage of 2;5 V. The measured lower end of the inductance tuning range is 3;2 nH with estimated resonant frequency of 5;6 GHz and a current consumption of 13 mA. The inductance value can be tuned up to 23 nH with a measured resonant frequency of 1;9 GHz and a current consumption of 1;9 mA. The switched differential bandpass amplifier is implemented in a 0;18 ¬Ķm CMOS technology at a supply voltage of 1;8 V. By activating the first or the second active inductor; the measured bandpass frequency can be switched between 100 MHz and 770 MHz. A modified switching concept of the active inductors can provide an amplifier with a bandpass frequency that can be switched between 125 MHz and 875 MHz in 125 MHz steps. Simulations indicate that the maximum gain is 16 dB for all 7 operation modes of the circuit.