In this paper, a grounded MOS only active inductor circuit is presented. The grounded active inductor circuit has a minimum number of MOS transistors. As a result, this presented active inductor circuit provides small chip area and low power consumption as 315 mu W. Also, the proposed circuit has tunability property and the active inductor can operate in a wide frequency range between 10 MHz to 500 MHz. To analyze the performance of the proposed grounded active inductor, a second-order notch filter structure is realized. The center frequency of the notch filter is selected as 200 MHz and the noise voltage value is calculated as 8.37 nV/root Hz for this frequency. The designed active inductor and filter structures are simulated by LTSPICE using 0.18 mu m CMOS process parameters.