Design of Folded Cascode OTA in Different Regions of Operation Through gm/ID Methodology

Abstract

In this study, we provide a systematic approach to the design of folded cascode operational transconductance amplifiers. In
order to maximize the efficiency of the MOS transistors, the design is carried out in three distinct zones of operation (weak inversion,
strong inversion, and moderate inversion) according to the gm/ID technique.
The developed folded cascode OTA operates in strong inversion mode with a unity-gain frequency of 430MHz and a DC gain of 77.5dB
using a 0.35m CMOS technology. It offers a 92dB DC gain and a gain bandwidth product of around 69MHz when operating in a mild
inversion mode. DC gain of 75.5 dB and unity-gain frequency are also characteristics of the OTA circuit.
In order to construct a Sigma Delta ADC for broad band radio applications, we set out to create a folded cascode OTA circuit.
This paper will proceed as described below. In Part II, we dissect the OTA structure of a folded cascode. The OTA circuit architecture for
the three operating ranges is shown in Section III. Section IV provides a scope for the design. After comparing our research to other
studies, we provide some final thoughts. weak inversion area restricts frequency to 19.14 MHZ.