Procedure for direct measurement of Common Mode Rejection

Abstract

To measure the Common Mode Rejection (CMR) of an amplifier, it is necessary to carry out the measurements of the implemented and finished circuit, and then perform the measurement of its behavior in real operating conditions. This measurement is necessary to evaluate the susceptibility to conducted electromagnetic interferences (conducted EMI) on the amplifier. In this work, a procedure of direct measurement of the CMR of an amplifier without altering the circuit is described. The measurements are verified by simulation with PSpice.

Keywords

• CMRR
• EMI
• amplificador operacional