Patent ID: 6681103
Filing Date: 2004-01-20
Classification: H03H

Abstract:
An integrated circuit comprising an image reject filter integrated monolithically with a low-noise amplifier (LNA) to reject an unwanted image frequency component of an input signal, the integrated circuit comprising:a driving amplifier having a first conducting terminal for providing an output signal, a second conducting terminal connected to an inductive degeneration element and a control terminal for receiving the input signal; a first resonant network coupled to the first conducting terminal of the driving amplifier for causing the driving amplifier to have a substantially high gain at a desired frequency of the input signal; and a filtering network coupled to the second conducting terminal of the driving amplifier for providing a substantially high impedance to the second conducting terminal at the image frequency so as to cause the driving amplifier to have a substantially low gain at the image frequency; wherein the filtering network comprises a tunable parallel LC resonator and a negative resistance generation network, whereby in operation the negative resistance generation network produces a negative resistance that substantially cancels inherent resistive losses of the LC resonator.