Folded Cascode Op-Amps – A survey

Abstract

In modern time, CMOS technology has evolved rapidly and has facilitated AMS IC’s to
dominate the current market by providing fast frameworks with low supply and low power
with reduced dimensions. Operational Amplifier is the most essential structure when AMS
integrated circuits are contemplated. Several designs with body driven approach are
presented, though this technique has gm low with factor of 4 to 5 than gate driven approach
in CMOS. Body driven technique presents various disadvantages of large input capacitance
and low trans-conductance (gm) however, the problem of latch up present in gate driven
approachiseradicatedinbodydrivenapproach.Thedownsidesofreducedtrans conductance can
be reduced with the help of positive partial feedback to improve the trans-conductance and
in turn enhances diverse characteristic Op-Amp parameters.