Topic
Operational transconductance amplifier
About: Operational transconductance amplifier is a research topic. Over the lifetime, 14358 publications have been published within this topic receiving 158733 citations.
Papers published on a yearly basis
Papers
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13 May 1994
TL;DR: In this paper, an ultrasonic oscillator drives a tool at a set frequency and an amplitude control runs the oscillator to set the vibration level, and a frequency regulator joins the amplitude and oscillator.
Abstract: An ultrasonic oscillator drives a tool at a set frequency. An amplitude control runs the oscillator to set the vibration level. A frequency regulator joins the amplitude and the oscillator. A control feedback loop, in the frequency regulator, keeps handpiece linear dynamics. An operational transconductance amplifier, in the oscillator, governs gain of the loop. A circuit connects to the control to retard the rate of current application over time to the amplifier. The circuit has switching to either retard the rate or reset for start up. The amplifier is a current output device with current directly proportional to the bias current and input voltage with bias as gain change for the loop. The circuit limits the bias to the amplifier to modify frequency response and output current. A capacitor delays application of the bias to the amplifier. Replaceable tools of various lengths or shapes positioned along an axis vibrate for surgery at the frequency and a wave length. Tools longer than one wavelength and of configurations tuned to oscillate around the frequency resonate as a function of their material, length and configuration. A flue surrounds the tool and has a hollow elongate semi rigid central body about an axis with a funnel, at one end thereof and a nozzle, at the other to direct annular irrigant/coolant flow therethrough. The funnel and nozzle are resilient. Reinforcing ridges, inside the nozzle, act to maintain concentricity between the flue and nozzle tip and channel irrigant thereabout.
785 citations
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31 May 2002
TL;DR: RF power amplifier modes Doherty and Chireix - themes and variations topics in PA non-linearity envelope feedback predistortion feedforward microwave-power amplifier design.
Abstract: RF power amplifier modes Doherty and Chireix - themes and variations topics in PA non-linearity envelope feedback predistortion feedforward microwave-power amplifier design.
680 citations
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TL;DR: In this paper, the operational transconductance amplifier (OTA) is used in voltage-controlled amplifiers, filters, and impedances for continuous-time monolithic filters, where the total number of components used in these circuits is small, and the design equations and voltage-control characteristics are attractive.
Abstract: Basic properties of the operational transconductance amplifier (OTA) are discussed. Applications of the OTA in voltage-controlled amplifiers, filters, and impedances are presented. A versatile family of voltage-controlled filter sections suitable for systematic design requirements is described. The total number of components used in these circuits is small, and the design equations and voltage-control characteristics are attractive. Limitations as well as practical considerations of OTA-based filters using commercially available bipolar OTAs are discussed. Applications of OTAs in continuous-time monolithic filters are considered.
651 citations
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TL;DR: In this paper, a new design methodology based on a unified treatment of all the regions of operation of the MOS transistor is proposed for the design of CMOS analog circuits and especially suited for low power circuits where the moderate inversion region often is used.
Abstract: A new design methodology based on a unified treatment of all the regions of operation of the MOS transistor is proposed. It is intended for the design of CMOS analog circuits and especially suited for low power circuits where the moderate inversion region often is used because it provides a good compromise between speed and power consumption. The synthesis procedure is based on the relation between the ratio of the transconductance over DC drain current g/sub m//I/sub D/ and the normalized current I/sub D//(W/L). The g/sub m//I/sub D/ indeed is a universal characteristic of all the transistors belonging to a same process. It may be derived from experimental measurements and fitted with simple analytical models. The method was applied successfully to the design of a silicon-on-insulator (SOI) micropower operational transconductance amplifier (OTA).
604 citations