Operational amplifier immune to EMI with no baseband performance degradation

An operational amplifier (opamp) input stage achieving a high degree of immunity against electromagnetic interference (EMI) is presented. Unlike previously proposed topologies, the novel circuit does not show any significant penalty in baseband operation. The effectiveness of the proposed solution and its robustness to mismatch and process variations is tested by simulations performed with reference to the AMS C35 0.35 µm CMOS technology.