Method and apparatus providing cancellation of second order intermodulation distortion and enhancement of second order intercept point (IIP2) in common source and common emitter transconductance circuits

摘要

A transconductor circuit includes a first input device M₁ and a second input device M₂ each having a control terminal coupled to a radio frequency input signal, and a bias setting device M_B having a control terminal coupled to the radio frequency input signal and an output coupled to the control terminal of each of said M₁ and M₂. M_B is partitioned into two equal sized bias setting devices M_B1 and M_B2. In the preferred embodiment M_B1 and M_B2 are coupled to the control terminals of M₁ and M₂ for establishing a bias voltage at the control terminals of M₁ and M₂. The circuit is shown to substantially cancel second-order intermodulation distortion and to enhance a second order intercept point.