Compact CMOS Miller OpAmp With High EMI-Immunity

In this work, a CMOS Miller Operational Amplifier (OpAmp) with high immunity to electromagnetic interference (EMI) is proposed. The proposed OpAmp has unique features, such as compact power and low output offset voltage, when compared to the classical Miller OpAmp and the robust Miller OpAmp reported in the literature. The proposed compact Miller OpAmp has a reduced area, when compared to the robust Miller OpAmp. The output offset current modeling equations are derived for the proposed compact Miller OpAmp including the body effect and channel length modulation. The results are validated with simulations in the presence of a test EMI signal of 1 Vpp in 1.8 V, 0.18 mu m CMOS technology. The power consumption of the proposed compact Miller OpAmp with source degeneration resistance R-S is 8% less and the area is 5.6% less than the robust Miller OpAmp with source degeneration resistance R-S. The performance result shows that the maximum EMI-induced input offset voltage for the proposed compact Miller OpAmp with source degeneration resistance R-S is 4.6 mV over a wide frequency range from 1 MHz to 1 GHz, which is lower when compared to the classical Miller OpAmp and the robust Miller OpAmp with source degeneration resistance R-S.