US Patent 10425044 Cancellation capacitor for aliasing and distortion improvement

A circuit includes first and second operational amplifiers, each including positive and negative inputs and first and second internal nodes. A mixer couples first and second input nodes to the positive and negative inputs of the operational amplifiers. The mixer switches the first and second input nodes between the positive and negative inputs of the first and second operational amplifiers in accordance with clock signals. A first cancellation capacitor couples to the first input node, and a second cancellation capacitor couple to the second input node. First and second switches selectively couple the first cancellation capacitor to the first and second internal nodes, respectively, of the first operational amplifier. Third and fourth switches selectively couple the second cancellation capacitor to the first and second internal nodes, respectively, of the second operational amplifier.