Patent ID: 7808319

Claim:
A differential amplifier circuit for improving linearity, comprising: first and second loads; a first output terminal for the first load; a second output terminal for the second load; a differential amplifying stage comprising a differential stage for amplifying a voltage difference between a first input stage and a second input stage, and a biasing current source for biasing the differential stage; and a non-linearity filtering circuit for filtering a nonlinear signal generated from the differential amplifying stage, the non-linearity filtering circuit comprising a first cross circuit including a first transistor to connect the first and second output terminals, and a second cross circuit including a second transistor to connect the first and second output terminals, wherein the first transistor has a drain connected to the second output terminal, a gate connected to the first output terminal, and a source connected to a ground; the first cross circuit further includes a first bias voltage source stage for applying a first bias voltage to the gate of the first transistor; the second transistor has a drain connected to the first output terminal, a gate connected to the second output terminal, and a source connected 5 to the ground; and the second cross circuit further includes a second bias voltage source stage for applying a second bias voltage to the gate of the second transistor.