A 0.5 V Operational Transconductance Amplifier Based on Dynamic Threshold-Voltage MOSFET and Floating Gate MOSFET Inverters in 180 nm CMOS Technology

Subject Areas : Renewable energy

Amir  Baghi Rahin ¹ (Department of Electrical Engineering- Sardroud Branch, Islamic Azad University, Sardroud, Tabriz, Iran)
Vahid  Baghi Rahin ² (Department of Electrical Engineering- Sardroud Branch, Islamic Azad University, Sardroud, Tabriz, Iran)

Received: 2022-04-01 Accepted : 2022-08-01 Published : 2025-02-19

Keywords: low voltage and low power, dynamic threshold-voltage MOSFET, floating gate MOSFET transistor, operational transconductance amplifier,

Abstract :

This paper presents a fully differential operational transconductance amplifier (OTA) based on the dynamic threshold-voltage MOSFET and floating gate MOSFET (DT/FGMOS) inverter with a supply voltage of 0.5 V. The proposed inverter in the structure of this OTA is a combination of the dynamic threshold-voltage MOSFET (DTMOS) technique (for all PMOS transistors) and the floating gate MOSFET (FGMOS) (for all NMOS transistors) in n-well process. In this circuit, feedforward and feedback paths have been used to limit the common-mode gain. The first stage has feedforward paths to eliminate the common-mode and the second stage has the common-mode feedback to stabilize the common-mode output voltage on Vdd/2. Based on the post-layout simulation results, the proposed OTA showed a gain of 61 dB with a unity gain frequency (UGF) of 1.1 MHz under 13 pF load capacitors. With the studies performed by Monte Carlo analysis, it was found that the OTA based on the proposed inverter can perform well under process variations and device mismatches. The proposed circuit in 180 nm CMOS technology occupies an area of ​​0.182 mm2 from the chip. Its power consumption is 17 µW and it can be used in low voltage and low power applications including portable equipment. According to studies, the use of DTMOS and FGMOS techniques can lead to the effective reduction of the threshold voltage of transistors and the good performance of the proposed OTA at low voltage.

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