Low pass filter with common-mode noise reduction

Abstract

A low pass filter includes a first amplifier stage and a second amplifier stage. The first amplifier stage includes a differential operational amplifier, wherein the first amplifier stage is arranged to process a differential input signal to generate a differential intermediate signal, the differential input signal having a first input signal and a second input signal, and the differential intermediate signal having a first intermediate signal and a second intermediate signal. The second amplifier stage has no common-mode feedback and is arranged to process the differential intermediate signal to generate a differential output signal, wherein the differential output signal has a first output signal corresponding to the first input signal and a second output signal corresponding to the second input signal. Since the noisy common-mode feedback is removed from the second amplifier stage, the overall common-mode noise of the low pass filter can be decreased.

Dependencies are inferred from the claim text.