A Novel Low Noise Active Inductor with Mutually Independent Tuning of Quality Factor and Inductance
A novel low noise active inductor with mutually independent tuning of quality factor(Q)and inductance(L)was proposed,which was mainly composed of dual gyrators,modulation branch,adjustable feedback resistance,transconductance enhancement branch and noise suppression unit.Among them,the dual gyrators were formed by the first gyration loop and the second gyration loop in parallel to obtain large inductance values.The modulation branch could not only reduce the equivalent parallel resistance,and thus increase the Q value,but also achieve a wide tuning range of inductance value;The adjustable feedback resistor could not only increase the Q value,but also achieve independent adjustment of the Q value and compensate for the Q value's changes resulted by tuning L value;The transconductance enhancement branch and the noise suppression unit reduced the noise of the first and second gyration loop,respectively,hence reduce the noise of the entire active inductor.By the deep cooperation not only among above circuit modules but also among the three configured external control terminal voltages,the excellent characteristics of Q and L values that coud be independently tuned each other and low noise were achieved.The simulation results show that the Q peak value can be adjusted from 674 to 5 083 with the regulation rate of as high as 153.2％at the frequency of 3.8 GHz,while the variation of inductance is only 0.3％.At 3.65 GHz,the L value can be adjusted from 6.1 nH to 15.5 nH with the tuning rate of as high as 87％,while the corresponding change of the Q value is only 3.7％.In the range of 2 GHz to 6 GHz,the maximum and minimum input noise of the actived inductor are 5.29 nV/√Hz and 1.75 nV/√Hz,respectively.
active inductancehigh Q valueindependent regulationlow noise
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