A 0.7V Time-based Inductor for Fully Integrated Low Bandwidth Filter Applications


A time-based gyrator is presented to implement active inductors in an area efficient manner. Using a ring oscillator to integrate the input voltage and a switched transconductor to inject current into the input node, the proposed gyrator achieves inductive input impedance without using either large resistors or capacitors. Realizing the gyrator in this manner makes it amenable for technology scaling. Fabricated in 65 nm CMOS process, the inductor operates from a 0.7 V supply voltage and consumes 528 uW. Measurement results show inductance values in the range of 150 uH to 1.5 mH can be achieved.