A Design of 1 V CMOS-OTA with Wide Input Range

Kenji TOYOTA  Akira HYOGO  Keitaro SEKINE  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E77-A   No.2   pp.356-362
Publication Date: 1994/02/25
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on High-Performance MOS Analog Circuits)
MOS analog circuits,  circuit theory,  analog circuits,  electronic circuits,  integrated circuits,  

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OTA (Operational Transconductance Amplifier) is a useful circuit in analog signal processing systems, especially in high-frequency applications. Important features of OTA are: infinite input impedance, electrically changeable transconductance (Gm), and much wider operation range without negative feedback such as in OPamp applications. The good linearity of OTA over wide input range is necessary to extend the application fields of OTA. Several techniques are developed to extend the input range with good linearity. In this paper, a highly-linear CMOS-OTA operating under 1 V power supply, is proposed. The concept of the proposed OTA is based on class-AB operation of two n-channel MOSFETs in the saturation region. By improving the input stage circuits, wide input range can be achieved. SPICE simulations are performed to verify the performance of the proposed OTA.