Design of a Novel Linear 3-Input CMOS OTA and Its Application to Filter Realization

Moonjae JEONG  Shigetaka TAKAGI  Zdzislaw CZARNUL  Nobuo FUJII  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E80-A   No.12   pp.2548-2554
Publication Date: 1997/12/25
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: Analog Signal Processing
OTA,  filter,  nonlinearity cancellation,  

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A novel voltage-tunable linear 3-input CMOS Operational Transconductance Amplifier (OTA) suitable for onchip integration of advanced monolithic systems is proposed. When a 3-input OTA is needed, a conventional 3-input OTA uses two 2-input OTA's and either grounds one of the 4 input terminals or ties two terminals. This paper presents a method to reduce the number of MOS transistors and to save chip area by designing a 3-input OTA directly. A CMOS pair technique is introduced s a solution to minimize a matching problem for control voltage sources. Simulation results show that the active chip area of the proposed 3-input OTA is reduced by 25% compared to that of a conventional one. The proposed 3-input OTA is applied to a realization of an OTA-C filter to verify the effectiveness.