Stepped gain amplifier with improved attenuation

Abstract

A switched gain differential amplifier is provided which includes first and second differential transconductance amplifier stages and a disabled dummy differential transconductance amplifier stage. The first and second differential transconductance amplifier stages have respective differential inputs that are coupled in-phase to one another and respective differential outputs that are coupled in-phase to one another. At least one of the stages is selectively enabled. The disabled dummy differential transconductance amplifier stage has a differential input coupled in-phase to the differential inputs of the first and second differential transconductance amplifier stages and a differential output cross-coupled out-of-phase to the differential outputs of the first and second differential transconductance amplifier stages. A common load circuit coupled to the differential outputs of the first and second differential transconductance amplifier stages and the disabled dummy differential transconductance amplifier stage.

Dependencies are inferred from the claim text.