Common-mode gain reduction technique and its applications

This paper proposes a common-mode gain reduction technique and a new approach for a balanced-type system design. Two design examples of a balanced-type operational transconductance amplifier and a balanced-type filter are given. The proposed scheme employs the proposed common-mode gain reduction technique together with the common-mode feedback (CMFB) network, which is used only to set a bias, to meet requirements of common-mode rejection. Compared with the conventional method, which uses the CMFB that has a higher gain than the one used in the proposed scheme, the proposed method shows reduction in design complexities and relaxation of the stability conditions.