Patent ID: 7203474

Claim:
An equivalent inductor circuits, comprising: a capacitor; a gyrator composed of a plurality of operational transconductance amplifiers and having said capacitor as a load, the operational transconductance amplifiers each includes a first differential pair composed of a first MOS transistor and a second MOS transistor, a second differential pair composed of a third MOS transistor and a fourth MOS transistor, a first current source for driving said first differential pair, a second current source for driving said second differential pair, wherein said first and second current sources produce identical currents, a gate of said first MOS transistor and a gate of said third MOS transistor are connected together, a gate of said second MOS transistor and a gate of said fourth MOS transistor are connected together, a drain of said first MOS transistor and the drain of said third MOS transistor are connected together, a drain of said second MOS transistor and a drain of said fourth MOS transistor are connected together, and a ratio of a value obtained by dividing a gate width of said first MOS transistor by a gate length thereof to a value obtained by dividing a gate width of said second MOS transistor by a gate length thereof is 1:k (where k is a constant), and a ratio of a value obtained by dividing a gate width of said third MOS transistor by a gate length thereof to a value obtained by dividing a gate width of said fourth MOS transistor by a gate length thereof is k: 1 (where k is a constant); and a resistor connected in series with said capacitor.