1,721,123 research outputs found
La scuola altrove. Tendenze in oriente
No full textThe article provides examples of current trends in the functional distribution of schools in other Eastern countries in order to identify good practices and ideas
150uA CMOS Transconductor with 82 dB SFDR
No full textA CMOS high-linearity transconductor useful for IC filtering applications is presented. It is based on a feedback unity-gain amplifier driving a resistor to achieve linear voltage-to-current conversion. Simulation results are provided on a design example using a 0.35-mum technology, powered from a 3.3V supply, and using a total dc current of 150 muA. The 3-dB bandwidth was 630 MHz and HD3, onto a load resistor of 20kOmega, was -82 dB at 1MHz
High-CMRR CMOS current output stage
No full textA novel current-mode output stage is presented which achieves high CMRR owing to an auxiliary high-gain feedback loop. Compared to the traditional solution, an approximately doubled transconductance is also obtained. SPICE simulations using the model parameters of a 0.8 μm CMOS process are found in remarkable agreement with expected results
CMOS Single to differential Current Amplifier
No full textA CMOS current amplifier which provides single-input to differential-output conversion is proposed. The circuit exhibits high CMRR and allows an electrical tuning of the current gain. A simple model of the circuit is presented and design guidelines are provided. Simulations with the model parameters of a 0.35-/spl mu/m process show good agreement with expected results
Adaptive frequency compensation for maximum and constant bandwidth feedback amplifiers
No full textWe present an adaptive frequency compensation technique providing maximum bandwidth closed-loop amplifiers. The approach exploits an auxiliary variable gain amplifier to implement an electrically tunable compensation capacitor proportional to the feedback factor. In this manner, the closed-loop bandwidth is kept ideally constant irrespective of the closed-loop gain. The proposed method can be applied to any amplifier adopting dominant-pole compensation. As an example, we designed a CMOS amplifier providing 66-dB direct current gain and 310-MHz gain-bandwidth product. For closed-loop gains ranging from 1 to 10, the closed-loop bandwidth was found never lower than 401MHz (noinverting configuration) and 229MHz (inverting configuration). A similar amplifier with equal gain-bandwidth product, but adopting the traditional fixed compensation approach, would exhibit a closed-loop bandwidth reduced to 33MHz (noninverting) and 30MHz (inverting) when the gain magnitude is set to 10. The enhanced frequency performance is obtained with a 48% increase in current consumption, whereas the other main operational amplifier performance parameters remain almost unchanged compared with the standard solution. Copyright (c) 2011 John Wiley & Sons, Ltd
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