An EMI susceptibility study of different integrated operational transconductance amplifiers

David Krolák – Pavel Horský

   This paper presents a comparative EMI susceptibility study of different integrated operational transconductance amplifier (OTA) topologies. We analyzed conventional well-known amplifier topologies based on the Miller OTA and folded cascode concepts with lower power consumption. The output dc voltage shifts induced by power supply and input common mode high frequency disturbances are presented. On top of the EMI susceptibility comparison, we discuss PSRR and CMRR within large and small excitation signal with a new simulation setup. Even more, the back-gate connections of differential MOS pair in OTA input stage are investigated for EMI susceptibility impact as well.

Keywords: CMRR, common mode, dc voltage shift, EMC, EMI, folded cascode, HF immunity, low power, Miller, operational transconductance amplifier, OTA, open loop gain, PSRR

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